Ok got a Punchout in for repair today, fired it up and see (c) Nintendo at the bottom of the splash screen instead of (c) Nintendo of America. I haven't compared roms yet, but anyone else seen this?
The Japanese version of Punch-Out (punchoutj.zip in Mame) is like that:
The same applies to the Japanese version of Super Punch-Out (spnchotj.zip).
Edit: I just checked all of the U.S. versions of PO and SPO in Mame and they just say "Nintendo" instead of "Nintendo of America" too. My actual SPO boardset says "Nintendo of America" on that screen. I'll check my two PO boardsets later.