As I sanded it, it turned out the wood (basswood) was kind of cute enough to leave it natural.
Like McCartney I sanded the horns (I didn't care much for the original looks) but I did refinish it satin.
I filled the fret slots with epoxy.
This bass was a good beginners bass when it had frets, but wasn't spectacular in the sound department.
As a fretless it really came to live.
I like it that much that I seem to use this one all the time;
Before and after.

It's not mine, but the same.
This is the result after:
