Well, it is from a 1006 (but not the mint one I just got). More on this one to come but here is a pic of the bubbled part which (I think) is causing the trigger to slightly catch in SA mode. Luckily, the reset is super short so one would never notice it during normal firing. However, since I have a mint 1006 next to this one to compare it was noticeable. Playing with the trigger play spring is how I noticed...So, what is this part and since it is catching on the frame, could it cause the famous 3rd gen SA trigger click? I think maybe..

What is interesting is that this 1006 is a former PD pistol and I suspect it has clicked/stuck from day 1!

UPDATE:
02/20/2011 - This part was replaced and appears that although it caught slightly it was not the cause of the clicking. I will do a complete write up on putting back together 1006 #2 shortly.