Could they be unpara'd paras? Rebarreled since they wouldn't fit Canadian law, but already cut short for the US market and just, sitting there?
The barrels could have been replaced with as short as they could go, since they already had to take it apart...why not take advantage of the obvious desire for a shorter SKS and just rebuild them a little differently? It would be interesting to see one like this with it's original bayonet, to see if they perhaps were a little too short for the groove in the stock...or if they were ground to fit. Too short might indicate a rebuilt US rebuild...it would still reach the stock retainer, and go into the groove a little, but leave a gap in the stock groove.
Is there a similar type of barrel for a different gun that could have been modified for the SKS? Would a potential AKM market have been possible if the barrels were longer? It seems as if pinning a hi cap mag is not really an issue....is the AK lack up there simply because of barrel length? If there were folks in China trying to build a Canadian friendly AKM, Something akin to that AK/SKS Polytech monstrosity that recently appeared on GB.....barrels like this could have been available already....
I would like to see several of these and see if they are a mix and match of various guns, like many paratroopers were in the first place, early blade here, late pinned there...etc. If they were a pinned receiver, perhaps the replacement barrels would just go right in, no sweat...but the threaded barrel receivers needed that funky pinnned/threaded thing we see here.
I live close enough to Canada, it kills me that I cannot go up for a mini vacation just to hit the gun shops (and tire shops) to see what I can see. I nearly invaded once...but opted to get back on the cruise ship...Stupid hindsight.