Updates to my original review.
Strings
I decided to switch back to rounds. But it sounds good with either flats or rounds.
Electronics
I've sprayed the pots with cleaner twice, and twisted them a lot. The tone is still a little scratchy. It's not bad enough to be a big problem, I hardly notice, but its still there. Since I solder and work with electronics, its no big deal to replace them, which I'll do soon.
Nut
It works fine with no issues, but has some rough edges and spots that look a little unfinished. Its not noticeable unless you look very close. I was going to replace it, but decided I'll just sand the edges a little the next time I have the strings off.
Bridge
The stock bridge looks small and thin, although it works great and has no issues. I ordered a Hipshot high-mass bridge to swap out. Its a drop-in replacement since Gretch uses the standard 5 screw fender pattern.
So the bottom line is that its a great bass, that sounds and plays great out of the box. Nothing on it NEEDS to be replaced. But its easy enough to swap tuners, bridge, etc. if you're so inclined.