Sounds like a 5 wire humbucker. Assuming it is Artec (may or may not be):

Red and white together means it is pre-wired in series, you leave them as is.
Bare will be a ground for the pickup hardware.
Black is ground for the pickup wiring.
Green is your hot.

If you want to do a mod and separate the red and white, white will be a hot and red will be ground.

If it's from a different manufacturer the hots and grounds might be reversed, since pickup makers tend to do their own thing.