If one assumes the Britishbarrels & the replacement fore ends were fitted at the time of the conversion. Not all Savage rifles were worked on by having replacement wood & barrels fitted. They exist with factory original six & two groove barrels as well. Also those rifles that were completed with scopes were fitted with early scopes, not Mk3's.
I do wonder if the (specifically) Less Telescope rifles may have been part converted early on & then set to one side, the machining of the spigot subsequently being completed towards the end of the contracts in April 1946. It would at least fit in with the 'early style' front pads seen on all Savage rifles that I've ever seen, & might also have allowed a window of opportunity for replacement barrels & such like to be fitted, as per your observations.