With very few exceptions, all bicycle chains are 1/2" pitch, and 3/32" (for vintage) or 1/18" wide (BMX, Single speed, IGH).

You should be pretty much just fine with 5-speed stuff.

There were some changes at 6-speed, including a 6-speed "narrow", but still, probably not much of a problem.

Your incompatibility may come in with single speed. I have seen single speed chains with oversized chain plates, and skip links, but nothing like that in the last 30 years.