Heyyo,
Nope, Q3F began by using Q3 models, but once they got out some better revisions/patches, they threw in some special Q3F only models. I remember seeing the demopack man from ETF inna Q3F screenie.. so if you try and find the last versions of Q3F I'm sure you'll find some of these models there. And as for the game not supporting custom models? nope. Heck, it's not hard to even make bot personalities to go with them. I was lazy at the time, so I just copied other bots personality files and pasted them with diff names for the models that diddn't have any.
I think in total I had over 10 custom models. Horny from Dungeon Keeper being my fav, others were the tomb raider chick, and... well that's all I can remember, lol, go to that polycount site and you'll find most of the models I used.