They aren't all the same . . .

[Wild Skies]

My 20-ga. 0-frame Repro stock measures the same -- just a hair under 5" toe-to-heel as the bigger stock above.

The near end of production explanation doesn't square as the bigger stock's S/N is 28-8XX, the smaller gun gun above is S/N 28-16XX, I also have another 28-ga. with S/N 28-32XX that also measures 4 11/16" top to bottom. My friend's gun has a couple of other seldom seen idiosyncrasies: 70mm chamber stamping and it's sans the frame size stamping on the bottom of the rear lug.

The above is further evidence that, just as with Parkers, all Parker Reproductions were not created equal.