Just bought me first sks. i haven't shot it yet, maybe later this week. i just had a few questions that i thought maybe people here could answer. i picked it out of a crate, all the other rifles had long serial #'s, but mine is a letter followed by four numbers, why? it also has the blade bayonet on it, not the spike one. and from what i can tell, it has a threaded barrel and most of the parts are milled not stamped. thanks in advance.