I've recently purchased a couple of P229 frames off of GB that appear to perhaps be police trades. They are in excellent condition and mated well with a couple of uppers I previously owned. I installed the SRT in each frame and noticed in one of them there appeared something similar to a shim on the right side of the frame held in place by the sear pivot pin. It slides into a small grove and appears to become an inner part of the frame rail, and is necessary to keep the safety lever, sear and sear spring in tight alignment. The frame in question is an older German frame with an AE2XXXX serial number and is DA/SA. I've not seen this on any of my other Sigs, and wanted to know if this sounds like something anyone has any experience with. Sorry, don't have any pics to upload yet.

Some police frames had a magazine disconnect, could that be one?