Agreed that the serial number has been removed, just questioning that it means it was 'clearly' stolen. Of course it could have been, and I agree with previous posters to the point that it COULD have been, but I also know people on both sides of the border that in advance of changing legislation, changes in governments etc. have gone to great lengths to ensure 'the man' couldn't find or trace/track their beloved firearms. I think if one looked at the historical sale of PVC pipe and end caps there would be a corolated upswing related to political events. We have all seen an increase in the sale of 'well stored' firearms since the LG registry died, and there is more than one reason for that.
In the interest of full disclosure I bought the one without the serial number on EE mentioned above, from a very reputable seller on CGN I might add. The 'work' done on my rifle is somewhat more delicate than the example here but what they seem to share is that the removal was done many years ago judging by the patina over the area altered. With mine (maybe his one too) the removal seems to have been done with great care to not ugly up the gun. I agree with Mike Webb 'it's around a hundred years old, who knows where it has been' I don't agree that it means it's clearly been stolen although that is certainly one possibility. I bought the gun to shoot not to collect, I'm sure most guns her age have a few stories to tell.
What's it worth? Well like all things it's worth what two people, one selling, one buying are willing to agree upon. For me it was worth what I paid, serial number or not. (LEO/CFO were contacted to ensure the legality of the sale) Of course what most people are saying here is 100% correct, with the alteration it might not be worth much, if anything, to a historical collector.
Do I have my head in the sand, no, some time a long time ago the serial number could have been removed because it was stolen or worse. If you buy a milsurp that has seen service might that weapon have killed someone? Sure. Could there be other reasons the serial number was removed? Sure. (more than a few involve tinfoil hats). Would I remove a serial number, no. Would I buy anything that looked like the serial number had been removed in my lifetime (on the long side of forty headed to 50) no. Will I enjoy my rifle for what it is, yes.
Ps. I agree with Mike Webb on the ballpark value he mentions (altough I paid a little more) as it's condition as a shooter or 'parts' gun are largely if not the only determining factors given the removal of the serial number.