Actually we use Evolution Gun Works (EGW) for our bushings. We know the owner, George Smith pretty well, he's a great person. EGW makes other parts for us as well. We designed the bushing to work with the 97's lower recoil spring plug. The rest of the bushing is pure 1911.
The stock bushing can rotate if the steel recoil spring plug compresses the recoil spring when the slide is fully reward, which can allow the plug to back out of the retaining slot = out of place bushing.