Yes, I understood it to be what we call a GCC [Green Cheek Conure]. I have a female right now but had four in total, two males and two females -three of them were rehomed and I kept Codee, the female I have because I promised her owner that I would. She is now bonded to an old, severely handicapped, wild-caught ex-breeder Peach Front Conure so she has company and attention 24/7/365 but she still needs at least two hours of one-on-one with me.
Yes, they are both 'quiet' parrots but, I warn you, quietness in parrots is relative and, if you ever heard a cockatoo scream, you would understand why these are called 'quiet' species
But, in my personal experience and with the possible exception of species like quakers, sun conures, jendays and sundays which seem to scream just to hear themselves do it, all parrots are OK in terms of vocalizations IF they are kept the right way. Of course, for an apartment, you would want a 'quiet' species. I've never had a brownhead but I've had and still have other species of poicephalus [right now I have two senegals and two redbellies] and it is true that they are much quieter than other species. Having said that, I once took in a female Senegal because she screamed bloody murder all day long and the owner was afraid she was going to get evicted from her apartment, and Codee GCC was given up because of screams and bites but she never makes a peep here and never, ever, ever bites - she is one of the sweetest birds I have with the female Senegal coming a VERY close second!
As to which one... personally, if I were you, I would go with the one that likes me the best. I would also ask about their previous owners because birds that are used to a man, tend to like men better and birds that are used to a woman, tend to like them better BUT this does not mean that a 'man-owned' bird would not love a woman or viceversa. And, sometimes, they surprise you because my Zoey Senegal, which loved me from the very first and hated my husband was raised by a man - and the new bird I have, a black-capped caique, was raised by a man [and very well treated and loved by him, I might add!] but he took to me and goes after my husband every chance he gets. Parrots are difficult... one never knows with them. Sometimes they fall in love at first sight with a person, sometimes it takes them years [the male Senegal, Sweetpea, took 3.5 years to stop attacking me several times a day every single day and 1.5 years more to accept me as a friend]. The point is that it's always easier on the human when the bird likes him/her from the beginning. And this is especially true of newbies because they tend to be in a rush to make a personal pet out of the bird and get very discouraged and even resentful when months go by and the bird still doesn't like them. Parrots are not like dogs or cats - they are not people oriented, they don't understand submission or even obedience and discipline actually works against you with them - they are not even grateful for the food we give them! They are more like people than any other companion animal we might have. You need to learn their personal boundaries and accept them, you need to respect their wishes, you can't take them for granted and you can't impose your idea on what a good parrot is on them. Living with one is harder than having a difficult roomie who doesn't even speak your language
But, if you do everything right and are patient, consistent, persistent and loving, they reward you in ways I can't even begin to describe!
So my advice to you is to go back to the store and spend time with both parrots separately. Don't ask them to step up or anything, just observe them out of the corner of your eye [you should never stare straight at a bird in a vulnerable situation -as it would be for a bird in a store where strange people are in and out all the time]. Look to see which one stays close to the side of the cage you are standing without backing away, see if one of them actually gets closer, which one looks at you with interest, which one takes a treat from your hand readily [carry some almond slivers with you or pieces of walnuts]. Do these people vet the birds? Are they a rescue or a store that takes birds in on commission? Because anybody who leaves a pet bird in a store to be re-sold was NOT a good owner and any bird in a store is going to be -without the shadow of a doubt!- a stressed out bird so vet records are important. If they don't offer any records, look at what the bird is being fed [although most likely is crap], check its plumage [is it shiny and smooth or raggedy looking - are there black marks on the parts that are supposed to be green? both the brownheads and GCCs have a completely green back and wing tops, there should be no black whatsoever on them].
Now, personally, I would still take one of them even if they have black on their plumage or if they look ragged but be advised that, if they cannot give you vet records issued within the last six months, you will have to take it to an avian vet for a completely physical [and that means blood work!] as soon as you get it [and I would recommend doing it the same day because you want the stress of going there AND going to a new home to be over asap].