Timing plates all the same?

[Lbrown311]

Are all the timing plates the same? I know the advance and what not are different. I have a plate but need a 79 advance to go with the rest of the bike. There are a couple cheap ones on Ebay I would like to buy if all the plates are the same.
Thanks,
Lance

[crazy steve]

The '78-80 timing plates are the same, but the vacuum advance units aren't; those are year-specific. The '81 plates don't have the adjustment slots, so make sure you don't get one of those.