Nope.
You do know how teh submodel system works, right?
Submodels allow mdl files to contain more than one model. (For example, the garbagegibs model has 14 submodels containing random bits of garbage. Submodel 1 is a crumpled piece of paper, 7? an envelope, 13? a crushed soda can, and so on.) So the glassgibs mdl has 7 or 14 submodels or so, to have some random variants of glass. Now submodels are randomly selected unless they're things like weapons on grunts, so when these glass 'models' are spawned, the submodel is randomly selected thus allowing a random and non-uniform appearance. If you add extra submodels to the model, the game will just have a larger pool to randomly select from, which it will do automatically.
So, all you have to do is make extra submodels and the game will take care of the rest.