@hfpop: Nope. The only thing you can safely drop is the 'Regular' suffix. Any sane font rendering engine *should* assume that no suffix means medium.
c.f., fontconfig:
Code:
fc-match "Deja Vu Sans Mono"
DejaVuSansMono.ttf: "DejaVu Sans Mono" "Book"
(It will match on the right font no matter the case & spacing).
But that's for fontconfig, so I digress a bit.
TL;DR: No, trust FontForge.