HNAD!!!!! He's right. Fender grill cloth (even vintage) is on the bay a lot. Reasonable prices when you look around a bit. Let us know when you're ready to put it on and you'll get some good tips.
Removal is easy. Take the amp apart, chassis, possibly the reverb tank. Then you're to the baffle board. It will have bolts on each corner that come through the cabinet with nuts and washers on the inside. Take those out and carefully remove the baffle board so as not to damage the speaker. This is also a good time to keep the cat away from the speaker. Remove the staples and the old cloth comes right off.
Now I'm off to bed.