Saturday is also Free RPG day (Jun 19). I don't remember their Old School D&D collection being huge, but there are definitely some modules and old rulebooks kicking around. I grabbed the copies of B/X they had a while back, but there might be more.
Here's the store info:
STRATEGIES Games & Hobbies
3878 Main St.
Vancouver B.C. V5V 3N9
Mon-Wed: 11-6, Thurs: 11-7, Fri: 11-9, Sat: 10-6, Sun: 11-5
Vancouver Red Box: a site for old school D&D