Have you tried the Sig site as well? I know they have parts on there are well.I picked up a new P-220 Carry SAS Gen 2 over the weekend, I didn't think I would like the E-2 grips, so I ordered Hogue rubber side panels.
I actually like the E-2 grips, I love the gun but one thing I absolutely HATE is that trigger !
It has too much of a curve to it, and it cause me to get pinched every time.
I went to Brownells looked at a replacement that is more like the P-229 trigger , I hesitated to order it for reason unknown , went back last night and they are now on back order. So for now I will deal with the trigger until they ship my replacement when they get them in stock.
My M11-a1 has a nice trigger itself but don't like it's double action pull. Single action is smooth though