2 possible impacts the # of ply's might make would be bolt length for the bead rings. I don't know if there is a significant difference in thickness at the bead or not.
The stiffer or harder the bead material the more difficult it will be to keep a good seal on the bead ring. Should be fixable with a quality tire sealant.
We used to race late model dirt cars and ran bead locks on the outside wheels to keep them from rolling off the bead. in the spring It was always harder to seal up an older tire that had been sitting around from last year than it was a fresh new one.