Jsut because I have nothing to do but pester our guy in Bahrain, you can take the seal issue one step further and realise that vendors must get their Chigaco Rawhide or SKF parts from someone right?
Call your nearest bearing supply company and ask for an oil seal that fits the CR 3930 part number crossreference and they will get you an oil seal that is identical in every way, which may be the CR part in the CR box, or an SKF part in an SKF box, or whatever oil seal is available on the shelf.
My part ordered from GBS (their local branch in Ottawa, Ontario - not the Montreal branch listed here -
click arrived in just a day or so, and was quoted at $3 or something low. I could have ordered 100 seals if I had wanted to and the guy would not have batted an eyelash except to take a deposit. There are a lot of backdoor ins, when your let in to know about them or figure them out for yourself.
Geoff is right though, your quickest internet bet, is the JNZ guys.