You should be able to remove excess paint off that leg with some rubbing alcohol and cotton tips/wipes.
I'd recommend contacting the seller and getting a replacement. They ought to be able to source a spare pair of fists for you from TakTOM. TakTOM always supplies L-R replacement parts in pairs (it happened w/ my MP01 panels and MP Rumble piledrivers); so you'll probably end up with a leftover left fist (but more importantly you'll have the missing right fist). Fortress' arms are held together w/ 3 little screws, so it'd be easy enough to use a miniature screwdriver to open the right arm up and replace the fist.![]()