The aluminum handled bayonets are the 1891. These are the ones that had the majority of crests ground off. The 1909's have wood handles and have their crests. If you can get a good deal on one with the crest, I still have that extra corpsman's knife.
My information says they were exported to the US with the crests ground. If some were exported to Canadalater, they may not have been ground which may be why you see them. The law changed shortly after the US export.