is there a cheat sheet for the acronyms every one seems to use when labeling files?
hahaha See I wasnt the only one who had this question when I was a newbie! 
Yes there is.
http://forum.mybeatbuddy.com/index.php?threads/users-songs-with-different-requirements.7354/#post-31700
Enjoy
It’s been posted somewhere, but the actual meanings can vary depending upon the song’s creator.
K -keyboard.
So OPBk is one Press bass with keyboard. Some others:
DOP - drums one Press - a drums only arrangement.
OPK - OPBk with the bass removed. An arrangement for bass players.
K - can mean piano, e-piano, organ, or a mallet instrument, i.e., vibes, etc.
H - usually horns, of any type.
G - usually guitar
S - generally Strings, but could be sax.
Traditional arrangement - has intro, main loops, transitions, etc.
Jam version - a modified OPB, set up as a prejam in the intro, a jam main loop that
repeats until you don’t want it anymore, and a post jam outro that ends the song.
OP = original post or more commonly here on this forum, one-press
OPB = one-press bass
DOP = drums one-press
OPBk = one-press bass and keys; derivatives include s for strings, h for horns, etc
NP = non-percussion