Yes, I think the only guys you could really consider "members" would be made guys.

But I guess that would be up to peoples' opinion, since there's no formal designation.

Most people would definitely say Marco D'Amico is a "member" of the Outfit, though some are of the opinion he was never "made."

If you're asking if the Outfit has like a junior membership program or something, not that I've ever heard of.