It's probably best to get measurements for yourself and check.
The same "bolt in" installation is widely accepted for '61 - '64 and while it does technically bolt in, it's not right. The problem in this case is the location of the shock mounts. They are a little farther from center, which cause the shocks to hit the frame with the truck in use and makes it more difficult to install the shock and the bolt diameter is different, which makes it more difficult to install the shock. I think the spring perches are also a little different but they actually are close enough to work. I personally do not qualify it as a bolt in since it does not function properly if it is only bolted in. It requires modifications.
'68 and newer uses wider brake drums. That could be useful, depending on your plans.