I'm not sure enough of Papp's inside game to be able to make a definitive call, but I suspect he has trouble with Carmen's work rate and rough-housing and ends up losing a decision. He seems to like to keep his opponents at range and keep the pace quite slow, mostly pot-shotting. I don't think he has the kind of boxing-and-moving package that really beats Basilio. You never know, though.
The pace in his fights were usually slow because his opponents knew what one mistake could cost them. He would wait and bait his opponents, he wasn't one to outright press the fight from the get-go because he could more than handle anything they had to offer on the outside. Not that he was a great out-fighter due to his small stature, but because he was technically sound enough to keep out of any profound trouble there until his shots started to slip through and his presence was felt. He was kind of like a MW Saldivar in that regard, just more of a head hunter. A fight with an all out rough-houser like Basilio would've been very interesting indeed. I tend to think it's the better pure boxers that would've given Papp trouble rather than the pressure fighters or punchers, though. Not to mention he'd be the naturally bigger man here. Awesome matchup though, no doubt about it. Papp vs Eduardo Lausse would be one for the ages as well.