I don't think most brothers really thought Gina was better looking than Pam back then, not even Martin...just better girlfriend material. It's just that Gina got a lot of props from "House Party 1", where she stripped down to her draws in that bedroom, giving us a glance at that tight body. A lot of young cats couldn't get that off their minds for a while. Those young dudes in the theater that day acted like they never seen a girl. So I don't think those extra props had all that much to do with her having the lighter skin. Stripping down to her panties may be how she got her role on Martin in the first place. If that didn't make her look better than Pam, then it sure put her on par with her. It seems that Martin wanted a shot of Gina in real life, and got sued. That's why there's no way I could be an actor, playing the role of the husband or boyfriend of a fine sister. I'd be over her crib every night tapping that ass for real, disguising it as rehearsal.
Body wise. If you like the gymnastic build, where hips don't matter, than you'd probably thought Gina had the better body. If hips did matter, then you'd probably thought Pam had the better body.
Face wise I'd have to give it to Gina, but only slightly, especially when they were young, and when she played in "House Party 1". Although not ugly, Pam was a little too plain jane in the face. One day she could look one step ahead of Gina face wise, and the next day she could look one step behind her face wise. Meanwhile, Gina stayed pretty much the same without having to do as much to her face. But like most said, Gina didn't age too well later, and that was mostly because of her medical condition. To sum it up, I'll just say Gina wasn't the prettiest of the light-skinned girls and Pam wasn't the prettiest of the dark-skinned girls.
But I do know one thing, they both did a lot of training to get those bodies.