Speedplay Frog grease port

Does anyone happen to know what size screw is used in the grease ports on Speedplay Frog pedals? I've been meaning to replace one with a stripped head.

Incidentally, I have two pairs of the pedals, and one pair has screws with hex sockets, but the other has Phillips-head screws. The screws seem to be the same, otherwise. The stripped head is the socket-head-type.