As far as I have heard, today's manufacturers build their 1911 series to accept after market grips. There's a thread somewhere here with claims that some of Para's models do not. I don't know because I don't own any Paras. I know that several years ago Llama made a so-called 1911, branded as Firestorm, with the grip screws spaced so that it would not accept aftermarket grips, but they are out of business now. The late Firestorms, made in the Philipines did use spec grips.