ok well i have this track stem and bar for sale. someone asked me if it's a mod.2 or a mod.3 stem, how do i tell the difference.

isn't mod.2 and mod.3 only in 2ttt stems? and i believe the only difference is the angle?

I think this will help...

so i'm guessing my model is the m14 pista due to the angle of the stem

Yes but the stem is mod 1 maybe? Well as you said it depends on the angle apparently.