Official Hong Kong Super Nintendo with 50/60Hz switch

You sure they were modified by Mani (or someone else on their behalf, outside of Japan)? Evidence shows that everything was done in Japan by Nintendo: the box and manual says "printed in Japan" and the console itself bears no traces of Mani. Mani were indeed manufacturing Game Boy consoles and games for Nintendo in China (and they were printing "Mani" on all the PCBs, as well as boxes and manuals), but not home consoles. Hong Kong Famicom, Super Famicom/Nintendo and Nintendo 64 were all made by Nintendo, not Mani, they were just distributed by them. At one point around 1995-6 Nintendo started shifting production from Japan to China (e.g. Game Boy Pocket/Color, Nintendo 64 joysticks etc.), but this was not related to Mani.
BTW, have a look at the patent, the diagrams start at page 18. The patent was submitted in August 1992. I'm not technical enough to fully understand the document, but this date of 1992 hints that the same conversion system might have been used in both HK FC and SNES (the HK FC was released after 1990 in HK, much later than Japan, I need to check the box/manual to find a more precise date).

I'm not so sure, in fact I have 4 different versions of the HK SNES/SFC box and manual, and it seems that the SFC was still being distributed when the SNES was too. Mani relocated their HK office at the time, so you have some manuals of different versions with different addresses. It's a good way to tell that both PAL and NTSC models were being distributed at the same time.

This is interesting, I forgot to take a picture of my lockout chip, but the mod surely looks clean on my console. Can you show us how it looks on yours?


P.S. there are HK FC units with Makko (Bung) A/V mods, which are obviously HK made, but the HK FC was never sold like that by Nintendo (I have the manual, it's not A/V by default, just RF), they are after-sales mods done by shops/private guys.