There was a special run of 200 Model 29-3s made for Lew Horton in 1985. It was called the "44 Combat Magnum" and featured a 3-inch barrel, blue finish, round butt, and contoured wooden stocks with finger grooves. The serial numbers were in the ABL2900 range.

S&W changed to an alpha numeric serial numbering system in 1983 and started with AAA0000 ( the last N-prefix serial number was approximately N960000).

It is hard to tell exactly what Model you have, but it could be a Lew Horton 44.

Bill