Hi, I'm not a great expert but as previous should have 6061 stamped
on the dropout and have a flat cap. It's very difficult to tell from the side
if it is a flat cap or not (as a curved one with a bit of a shadow looks the
same).
Having said that some of the newer bikes (ie Outpost are 6061 and have a flat cap (tho geometry is totally different).
Looks like a larges size frame (is it about a 20 ?) just thought the gussets
didn't scream Zaskar to me.
Whatever it is you have a nice aly GT for not much.
PS if after all this anyone has a spare mech hanger (think it's type 2 to fit
a 96 Backwoods. I'd be grateful to do a deal !).