NEITHER lens has a tripod collar, nor do you DEFINATELY need one. the collar would help balance slightly and make vertical to horiziontal adjustments EASIER.

I shoot a 100-400L IS and can tell you this...

IS (2ND generation on 100-400, 1ST on 75-300) is a great tool when needed, but DON'T rely on it.

the tripod foot to me is hardly used(HAND HELD), but the lens is 4POUNDS ? , so one is A MUST on this sized lens for tripod mounting.

L glass makes images crisper, warmer, sharper.... though PS can warm an image too.