Is it possible men's graphite wallet is made in USA?
I can't say so definitively but it most likely is possible, as they have been moving more production over here. Spain and France have generally been more common origins for men's SLGs. I have SLGs from Spain and France and haven't noticed any differences in quality. Coincidentally, most of my favorite items are MIS (Made in Spain).
There should be a date code stamp on an inner pocket that you can look up online to find the origin and month/year of production. I understand some MIUSA bags have cloth tags instead of leather date code tags, but I doubt a wallet would have a cloth tags because there's no fabric lining. I really don't know because I've never handled a MIUSA SLG myself. If your wallet either doesn't have a date code or MIUSA tag or has an MIF or MIS date code but no origin stamp, I would contact LV as that would probably be a manufacturing error.
Since you bought it from the boutique you can rest assured it is authentic LV. Use it in good health and enjoy, it really is a good wallet!