There is only one known with a 4-inch barrel and bright blue finish. Two are known with a 4-inch barrel, 4-screw frame, and nickel finish. All the Model 29-1s known finished in bright blue have a 3-screw frame and an extractor rod with an old style, right-hand thread. The two finished in nickel have a 4-screw frame and an extractor rod with an improved, left-hand thread and are a true -1 model variation. There are approximately thirty-five Model 29-1s known in total, so the -1 is rare in its own right.
All but one or two of the Model 29-1s were shipped in 1962. Probably based on production scheduling, implementation of the improved cylinder stop with the deletion of the cylinder stop plunger screw resulting in a 3-screw frame was made before the supply old style extractor rods and stems was exhausted, thus resulting in the "odd" configuration for most of the Model 29-1s reported to date.
Bill