I think it'll look like a primered truck that needs a paint job.
Don't expect to hear "nice paint job". Most comments will be "what color are you going to paint it".
If your paint is in good shape pinstriping would be a better idea. If your truck's a p.o.s. the flat black will hide a lot and make it look better. Three or four spray cans and a roll of masking tape should do the trick. Estimate: $10 to $15