I concur.
I don't worry about how old the beav are when I make lure out of them, but I do watch where they come from. I like to keep the castors seperate from other areas unless I kill all of the beav off in an area. I really don't think I have to worry about this anymore though as I have a few different jars now, of castor from specific areas from a few years ago that were kept seperate for the reason that I made lure while I was trapping and wanted to make sure the beaver from colony A weren't baited with their own castor. I kept it seperate, Colony A and B, C , D, ........
Now, I really don't care, as I mix it together and I doubt the beaver could tell if some of it came from a colony mate when it is mixed with those of other colonies.