I've recently purchased legit U.S. Pokemon Red and Yellow Game Boy cartridges with their original batteries still holding saves.
The Red save has what appears to be a YOSHIRA Surfing Pikachu in the party, while the Yellow save has what appears to be LINKE Mew in the party (though based on the levels of Pikachu and Mew, neither seem untouched). Seller of the Yellow cart says it was from a Pokemon Stadium Tour back in the day, which seemingly jives with the LINKW Mews info here as well as some old Azure Heights forum posts (such as this one) I found.
Seller of the Red cart says they were a winner of the October 1999 Nintendo Power magazine Issue 125 contest that gave away 1000 Surfing Pikachus. Interestingly, the OT being YOSHIRA contradicts Bulbapedia, which says the OT should be NINTEN. But I can't find any other evidence documenting NINTEN as the OT, though I did find that ニンテン (Japanese for NINTEN...at least according to Google Translate) was apparently the OT for a different Japanese Surfing Pikachu distribution. So I'm wondering if the OT was transliterated and incorrectly copied over at some point and from then on just assumed to be accurate. The fact that the OT of the Surfing Pikachu on the Red save is YOSHIRA is interesting because YOSHIRA is also the OT of the Nintendo Power Mew distribution from Issue 127 in December 1999, which came only two months after the Surfing Pikachu distribution, so it would seemingly make sense if Nintendo of America used the same distribution technique/machine/software/etc for both.
Note that I posted about the LINKE Mew a while back on another thread but it didn't seem to gain any traction. However, unless I'm mistaken (which is entirely possible), neither a legit YOSHIRA Surfing Pikachu nor a legit LINKE Mew have otherwise been publicly preserved on this site or elsewhere. So I've dumped the saves and am attaching them here in hopes that the community can review and see if it's possible to verify authenticity?
POKEMON RED - Copy_SurfingPikachu.sav POKEMON YELLOW_2021.10.12-13.24.38 LINKE MEW - Copy.sav