[racket] History question about ?

Common Lisp's convention w.r.t predicate names appears to be all about 
the p or -p suffixes. My question is: Did older lisps use the '?' 
convention before CL, or was Scheme the first to conventionalise the use 
of ? in predicates?

Sorry for the off-topic question, I couldn't find any definitive answers 
online, and figured there's bound to be someone here that lived through 
the development.

Thanks,
Charlie.