Safariland ALS Shoulder Holster for S&W 3rd Generation?

I own several S&W 3rd generation "compact" pistols (3953, 6906, 6946). I would like to buy a shoulder holster (vertical) for them. After much research, the holster I see that I like the best is the Safariland Model 1051 ALS Shoulder Holster. Unfortunately, Safariland does not list this holster as fitting my guns. I'm wondering if anyone has had any success using this holster with these guns, and if so, the holster made for what gun?

My first guess, would be the Sig P228, as many holsters made for this gun will fit the Smiths. The ALS holster locks the pistol into place by using the front edge of the ejection port, so the critical thing would be the size and location of the ejection port.

Anyone have any knowledge as to whether this would work?

If the particular holster you mention is of kydex or other thermoplastic construction, I doubt it will fit anything other than the weapon for which is is molded. I work for a PD that mandates Safariland ALS duty rigs, and even such tiny changes as slightly reshaping the slide to accomodate a different extractor system will keep newer variants of existing pistol models from fitting the existing ALS holsters. I had two Custom Shop P229 pistols that would not fit into my duty rig, that was made for a standard P229. It seems the Custom Shop SIGs had a slightly wider slide, so that FCS could be milled into the slide. When SIG recently changed the P229 to an external extractor, the new pistols would not fit the existing ALS holsters.

Rexster, Thanks for sharing your experience. I wish your information had been different, but I guess we have to live with what we get.