if its locked I'm betting theres a good reason, like the graphics engine is linked to the physics engine and if you uncap it you get weird stuff happening in game.
Same with with most Bethesda games, like the later Elder Scrolls and Fallout titles. It is actually possible to force the frame rate above 60.
Object in game start shooting around like crazy when you bump into them. You can actually die from a can kicked into a wall that shoots back at you.
Gamebryo, thats what I was thinking of.
It was fine when it first came out, but its been surpassed by many modern 3D engines and it really shouldnt be used any more.