I grew up in Montrose and remember them as a catalog company. By the time I started climbing in 1965 Sports Chalet had opened in La Canada so we'd go there for gear. Sports Chalet I believe was the first mountaineering store in Southern California, I still remember the stern German who opened it.
There was the "Saddle Shop" on Foothill Blvd. in La Crescenta that may have been affiliated with the Eiger Co. I bought several pairs of kluttershoes from them, they were cheaper than Sport Chalet. You could get a pair of leather climbing shoes for around $10, Kronhoffers were out of my price range at $20 a pair.
Not sure if folks out there knew of anyone from Post 4 Mountaineering which was sponsored by the La Crescenta Presbyterian Church. That was the group I started out with and nearly lost my life on more than one occasion, despite the casualties we had great fun. Such fond memories of those days with a smog filled sky heading out to Stony Point or down to Tahquitz with my buddies.