First off, Ger, I confess to a complete ignorance when it comes to the DC appearances you quote. I take your word implicitly regarding those. However, when it comes to the Hillman Billy the Kid story, I looked at it again and then went and checked my index card done 20 years ago: same results. I see no Robinson here. My card says Meskin (w/Roussos? or Starr?) and that's still what I see. Starr is most likely pencilling this with Meskin doing the inks. Possible some Roussos inks as well.
As for the Prize work, give me the titles/issues/stories and I'll see what I can see. And remember, I haven't SEEN the DC material you refer to. I could never afford the books and was much more intrigued by the "lesser" publishers of the day.
Peace, Jim (|:{>