Is Delhomme's completion % similiar to Marino's? If so, yeah. And seeing as how you continue to bring WRs (something that's absolutely meaningless in this discussion) into this, I'll point out the fact that Pennington had a ridiculous completion % (the highest in history) while playing within a very mediocre offense.
This discussion has nothing to do with throwing long balls and hitting receivers in stride either. If you care to look, there's a MASSIVE drop off in completions beyond 20 yds. Even the league's elite QBs miss long throws often.