I finally got my new sear housing block from Brownells. I ordered two about a month ago, but got rear night sights instead. Took a few weeks, but they made it right. Anyway, I noticed a few differences from the one installed in my M&P 9, serial number MPA98xx. First, the sear deactivation lever is straight, not curved at the top, and the sear is silver in color, not blackened. Anyone know if these are newer, or older designs? I only care for curiosity, I know functionality will not be affected. I bought a M&P 40 from Buds with the mag safety, so I might through this in. It was origionally purchased for experimentation with trigger jobs...we'll see.