Hi, and welcome to the Forum!
For starters, try looking here for parts for your '65 4001 -
http://www.the-music-connection.com/ricpart.htmAlso, Rickebacker's own boutique has replacement parts (horseshoe & toaster pickups - modern, but they "look the part", pick guard - may or may not fit your 4001. Call Rickenbacker directly to inquire before you buy, if you buy from them - 714-545-5574).
You have yourself a VERY nice vintage bass! Good luck, and I hope you find what you need!
Jim
ps - check out this other awesome RIC forum as well -
http://www.rickresource.com/forum/