Mark on tang of Pioneer

[TexMex]

I have a red old cross Pioneer with a brass liner. I understand that this knife is likely from 1975-1985 due to the small V in Victorinox on the blade tang. On the reverse side of the tang where the date is normally stamped for Soldier models, there's a small burr. I'm curious if anyone knows if this is a mark to signify this as a blemished model or if it's maybe just a wear mark from years ago.

[Aloha]

Looks like it was sanded?