This may be a stupid question....or even sound a lil queer. lol

I just finished a 12 week Test E / Anavar Cycle...and I was under the impression - where you choose to pin doesnt affect that specific muscle. Example -- if you pin in your legs, will your leg muscle grow bigger than other muscles? And ive been told the answer is no - it goes to every muscle evenly. But is this true? Cause I pinned in my glutes. And today i realized my ass is rock hard --- no where near what it was. My whole body of course got harder and grew muscle - but not like my ass. lol So was it because of that?