I have a 3rd Gen probably born around '89 and noticed a "1" clearly stamped on the trigger guard and was just curious as to what it meant,if anything.

My 3906 is a little higher SN than yours, square trigger guard (were they all?). It also has the same stamping in this location. Great old pistol, eh?
XAVMECH

I'm not sure if those were all square,but have a 5906 basically the same pistol but hi-cap manufactured at the same time with a round(er) trigger guard.Both are as predictable as Old Faithful.

The original trigger guards for the 3rd generation S&W pistols were squared. The 3906 was only produced for a couple of years and was discontinued before S&W changed the 3rd generation design to rounded trigger guards.

The serial number range a 3rd gen would show up with a round guard will differ quite a bit between models. Partly because of the quantity of one was made vs the other(s), how quickly one model sold over the other, and because they were made in groups.

The "1" is actually a "T" (used to be a "P") and is one of the last inspector's marks before it is ready to be shipped.

LOVE 3rd gen pistols!! They just work all of the time, and will feed anything.

Okay I can see the "T" now.



This 5906 was produced in January 1990 according to what I was told by S&W and had the re-designed trigger guard,so guessing that it may have been introduced during the transition period as the 3906 was discontinued.
Thanks for the additional info.

I wonder if they meant redesigned from the 2nd generation squred trigger guard.

Like you mentioned, the 3906 was only made for the first year or two of 3rd gen production and one of the changes made during the Automatic Improvement Program (AIP) was they made the trigger guard almost 3/16" longer for gloves.