You can't expect HK to stock every single size of Nut, bolt, screw, washer etc. Just buy the M2 x 20 and use it for every job and cut the excess off. There is a Phillips head 2m x 12 or a 2.5 x 12 hex, won't they do the job? because HK simply don't sell an M2 x 12 hex bolt. Sometimes in the RC hobby we have to make do with what's available and if what you want isn't there then make something else do the job. Sorry.
I have a large collection of HKs nuts, bolts, washers and hardware and apart from a few deformed pieces in the chrome department I've found it mostly perfect and to spec. I just avoid a certain auction site for these items. Some of the were not fit for s****. I've got a massive amount of plastic zip bags too.
Yes, M2 (and M3, M4, etc.) threads are standardized as to thread pitch unless a non-standard pitch is specified. So M2 screws, nuts, blind nuts, etc. from this site all work with each other. Same for M3, M4, etc. Cheers!
Even if they provided a closeup of a single screw it wouldn't tell you any more than the written description tells you. They're 2mm dia x 10mm long hex socket head (Allen head) screws ... end of story. Cheers!