Yep. Just remember, the more complex the item (and in this case it would be the chemistry of the stocks) the harder it is to enchant. So for example, you may enchant a few bird bones and some sood ash mixed together and tied with a leather cord and coated with bee's wax into becoming a power focus easily enough. However, using pieces of plastic, wire, and superglue would make it tougher, since they are refined, complex compounds. Trying to enchant a cyberdeck or car would be next to impossible, but could be done with enough Karma and time. So if you have focus that is "natural" like wood or ivory, you have a much easier time. And if you actually grow the try, chop the wood, carve the wood, and finish the wood yourself with "non modern" tools, then it gets even easier becasue the material is considered to be virgin, as in "no other aruas have contacted it."
Gabriel, who has a shaman chummer