it genuine fender reissue tweed that i then lacquered with an amber tint to give it the vintage look. i think they look all funky, dry and pale if you don't lacquer them, so i always do them that way.
here's a 54 pro of mine that i re-did two weeks ago with the brown 'linen' grill cloth (before i re-tweeded this one, someone had re-tolexed it in black and did a funky job on it):
it actually sounds pretty good for bass for an 'open-back' amp, since it has an original NOS Jensen P15N in it.