9422 variation without front sight provision|Winchester .22 Rim Fire|Forum|Winchester Collector

I have a model 9422 with no provision at all for a front sight, and with a decorative filler block in the rear sight dovetail. The muzzle end of the barrel appears perfect and unaltered in any way. Does anyone have any idea whether this was a factory variation, and if so, when rifles like this were made? I have searched the internet quite a bit and can find no reference to such a variation. I am new to Winchesters and would appreciate any ideas. Thank you so much!