20 years ago I had Heinie install his recoil spring and plug modification. It is a reverse plug and the dust cover was milled about 1/8-3/16" to make room for the collar that sweeps about 210 degrees. It is not a no milling parts swap.
It does not use a gude rod or a captured spring.
Clark makes a plug that looks like the factory plug but with a thick flange to prevent the tab from breaking and it shooting out.
It's a drop in for the most part. The Tab may need a minor about of fileing to fit in the slot already in the frame.