Not if it had a single safety to begin with.EGW, Ed Brown and Kimber use a design which requires a special pin to keep the two sides of an ambi safety working together. Those that don't use that method depend on the right side grip panel to do the job. If the ambi safety is a 'must have', spend the money for the best product. Get one that has wide levers and file or grind them to suit you.
Got it...tnx BillThe SIS is just another 1911 with a few special order details added. No reason that any quality thumb safety cannot be fit.