I'll check it out when I get to a real screen.
AFAIK anyone with a Magic attribute can bond to any Foci applicable to any skill/power that they have access to. So anyone with a Magic attribute can bond to a weapon focus.
Honestly I've never specifically looked for a restriction on Foci bonding. It could be RAW that any Magically active character can throw Karma and Nuyen at any Foci weather it does them any good or not. *shrug* Seen plenty of mages with Weapon Foci so you're good there.
