As far as I know, trads have grease nipples on the propshaft up to the last ones. My 2016 does.
Don't overthink this though. They dont need much attention, and even when they do it's only a tiny squirt.
The rear nipple is easy to access, being visible underneath.
At the front there may be one or two, and access varies by model. As said above, sometimes a hole in the floor may be necessary for access.
If you over grease, it can push the seals out, and grease will be flung out inside the tunnel.
