Well, if I had a choice and I wasn't to be questioned on my reasons for hiring, and I had a choice between a bloke who knows all about PC games, DjHero and the in's and out's of XBLA and PSN or a very pretty girl who I might/might not get off with, assuming I was single of course, i would probably pick the girl, being merely human and less than that, a male....
Regarding poor shop staff, games selling minions have always fallen into two categories, people like me, who knew all about the subject of games because we love them and play lots of them and love talking about them, and those who know nothing beyond FIFA and Need For Speed and will sell you whatever the Sony/MS/EA rep told them to sell, regardless of the games actual quality.
And that's a rule right there, time has not changed this, I have been buying games since the mid-80's for my humble Spectrum and I have either been served by staff who knew all or staff who wanted to sell you whatever they were told to sell.
If you are lucky you get the former, but often we get the latter.
Anyhow, release dates are variable, not everyone in a shop knows about every game, and if he/she/it is too lazy to read the release schedule he/she/it will be sure to give the laziest answer when asked, a simple shrug and I don't know, or we're not getting it in, so you just talk to the manager whose job it is to know these things, as he is ordering the stocks into the shop itself.
Oh, and you never need to bring an eejit with you when shopping, you'll invariably find one in almost every shop you go into.