If you are talking about the M11-A1, then those are not true P228 because They have a stainless steel slide. They are more like P229s with P228 grips on them. As a matter of fact the M11-A1 is listed in the P229 section of the 2013 Sig catalog.Just a note: They are(sig) making them again with no rails. I see it in all my gun & shooting mag's.
The P-229 started life with a P-228 frame and a slide machined from stainless barstock. First in .40 S&W, then .357 SIG and later in 9mm. Original P-228s have folded (By mandrel) and welded slides like the original P-226s that were made in W. Germany and then Germany after the wall fell. The first M-11s were the folded and welded slide pistols but now use slides machined from stainless barstock so these pistols are little different from the 9mm P-229s that were made and discontinued. Your pistol would probably sell for a premium but it's really not a "collectible". I say shoot and carry it.
I believe there needs to be some clarification. The P229 was designed specifically for the .40 S&W round. The P229 may have started life with a P228 frame, but if it did, it was modified and the magazine well was widened to accommodate the new wider mags for the .40S&W and .357Sig rounds. The 9mm P229 which did come out last, almost as an afterthought, probably did actually use an unmodified P228 frame.
I am sorry, but that is just not true for the P229, but is for the P226. I think you are confusing the P229 with the P226. The .40/.357 P229 mags have not changed from the beginning. They were wider at the bottom than the P228/early 9mm P229 mags and taper in about 2/3s of the way up to the width of the 9mm mag. Without the added width, the standard .40 and .357 mags (which are the same) would not have a 12rd capacity, which is what they originally had and what they still have.The original P-229 did not have an enlarged grip/magwell for the larger diameter .40 S&W cartridge and that's what limited it's cartridge capacity and the .357 SIG is a .40 S&W case necked down to take a .355" bullet. The only real difference are that the magazines feed lips were widened for the larger diameter case of the .40 S&W.
I am sorry, but that is just not true for the P229, but is for the P226. I think you are confusing the P229 with the P226. The .40/.357 P229 mags have not changed from the beginning. They were wider at the bottom than the P228/early 9mm P229 mags and taper in about 2/3s of the way up to the width of the 9mm mag. Without the added width, the standard .40 and .357 mags (which are the same) would not have a 12rd capacity, which is what they originally had and what they still have.
I have a 1994 .40S&W P229 which is rail-less and has triple matching serial numbers while not one of the first is still an early version P229. I also have a 1993 P228 and can compare the mags.
This is a picture I took a while ago. It is a 13rd P228 9mm mag on the left and unfortunately a 10rd .40 P229 mag on the right, but the mag profile is the same as the 12rd .40 P229 mags. The mag in the middle is the new P229-1 9mm mag (that has the same profile as a .40 P229 mag) for the new 9mm P229s that are based on the old/"new" .40/.357 P229 frame with the wider magazine well. It is difficult to tell from the photo, but the bottoms of the two mags on the right are the same width and wider than the P228 one on the left.
Yes the P228 and early 9mm P229 frames and mags are the same. It is the .40/.357 frames and mags that 57K and I are having a discussion about.I think they are the same.