Cutting gaskets is a common use for laser cutters. I made a carburetor gasket for an old tractor engine with mine. Gasket material should be safe to laser cut as it will likely be one of three material types, paper, rubber, or cork. I got my material at my local auto parts store.
If you can get the old gasket off intact, you can use a scanner and the tracing function in LB to create the new gasket.