should work out fine... if that is real auto primer you might want to watch out as some of it has larger particles and could cover up detail on a model. Something made for modeling would definitely do the job. That said some primers work just fine for model applications. Does it say "fine" or "very fine" on the label? if it doesn't you might want to spray it on a test piece first (as in something extra from an old kit) to make sure.
If you posted this in the auto forum you'll probably get a better answer from someone who paint cars a lot more than me... (I do mainly aircraft)