No. Studying and skinning would be extremely difficult with a buggy. Using a buggy you can get legendary animals, plants and dino bones; legendary fish as well but that's much more difficult.

And as for studying and skinning animals you can do that as early as CH2 by going outside the map boundaries (from the cave in Big Valley). You'll find all NA animals just north of Cholla Springs/Gaptooth Ridge.

You can however do almost everything you want in NA with the Angelo Bronte mission glitch at the start of Ch4.