The 60-3 was introduced in 1988 and the 3" barrel was discontinued in 1992, should yours should fall somewhere between.

The "-3" engineering change involved switching from a fitted front sideplate screw to a screw with a spring loaded plunger tip. The front screw holds the yoke in place and the change was made to reduced skilled labor costs by eliminating the fitting operation. The yoke is also different to accommodate the new screw. I suspect the hammer was bobbed after it left the factory.

$350ish???