[Steveb123]

I wouldn't count on that. I had a guy bring in is wing in his truck saying he could only turn the engine over (by hand) so far and then he felt resistance. He said he tried turning it over several times and each time it would get hung up with resistance… finally he got it to turn all the way through.

He'd put new belts on,

The OP had no belt installed at the time of cam turning. If the valve hit the piston top, it will simply push it down the bore slightly.
No harm done, unless the piston is siezed in the bore!

Cheers.