Thanks to JWillis for that chart! I'll print it out for the wall in the electronics dungeon (my dank basement). And thanks to everyone for your replies and input. This means all these years when desoldering components from circuit boards for the parts bin, I've been throwing out capacitors that I thought were faulty resistors.
To reply to other posts here, that band is definitely gold, not brown. It may not show up very well in the photo but it does appear sparkly. And since it's supposed to be 82pf at 5% tolerance according to the parts list in the service manual, the sequence of gray-red-black-gold is correct. And I have to wonder why they'd put a cap rated for 900v on a board that has at most 12v.
Yes, there were multiple versions of the C64 board over the years, and even different schematics for the same board (ie. my board is labeled with artwork/schematic #251137, but the service manual shows schematic #251138 for my particular board). Considering how many bodge fixes there are all over this board, it's clear they were revising the thing all the time. Since my board is dated '83, I used the service manual from '85 for simplicity. I do have the '92 service manual, but the information for my particular board is exactly the same as the '85 manual.
And since this all has been a mere curiosity for the purpose of learning, I'm not about to desolder and remove this cap from the board just to test it in an LCR meter. However, I do have a scrap board for parts that I could remove that cap from to test. For science!