Though I cannot see the card, a Reverse Holo Magneton typically is just that, a Holo Magneton. Holo's can be any card in a series, and depending on which set it's from, it could be rare, or it could be worth as much as a normal Magneton.
I'm afraid I cannot make any final calls without seeing it, but I foreign or not, they typically aren't worth much. Earlier sets, maybe. But now-a-days, not particularly