Do you mean the studio mixer board type fader caps? The old Rane MP22/24 had them I believe before they were updated to the "Z" models. I really liked the old studio mixer type caps myself. Really gave you a firmer feel. The MP24 was unique back then. I had an MP22 and it supposedly had the same faders (I believe Penny and Giles) but it didn't feel the same and the "studio caps" were much shorter in height.
I never managed to own an MP24 as at that point I had already become a rotary fan and moved in that direction.
Regarding unity gain, to be honest I don't know with the new Rane's, although it would be an easy enough test to perform. The older Rane's almost always had unity ticked off in some fashion (a wider tick, "u", etc), but the new ones don't really have anything to distinguish if you're at unity. Most likely Rane realized with the "dummification" of the dj, came a majority of dj's not even knowing what unity gain meant so why even bother.