I got a Reverse Holo Magnemite, and the resistance symbol is an empty white circle (like the colorless symbol without the star in the middle).
It's just a grey circle (means nothing) where the foil is normally cut out for Resistance. However for clarification, there should not be any Resistance on that particular card - the non-foil of that version doesn't have a Resistance either.
Source: PUI Rules Team (2003-11-20)