Not supported by a definitive statement to that effect in the RAW though.
You could take Lame twice , if you were a Centaur.
I guess the expression "Lame in both legs" is not one found in foreign languages.
Plus i could not find a definition of Lame that states only one leg is affected.
But it is your saga. If you want to play semantics with your players, it is fine for me After all it is your saga, and as long as you hare having FUN it is perfect. That is the objective of the game, after all: to enjoy the story the saga tells. If a +60 bonus for experimenting is ok for you, go for it