Yes. I have a four year old J-Classic V, and during the first 6 months or so that I had it it got some battle scars just with normal, careful use. The finish hardened up over time as it cured, but it is still pretty delicate. Part of that is just the nature of thin nitro finishes, but I think it's also a result of the process used by Moollon, which doesn't seem to result in finishes that are as impervious as other nitro finished instruments that I own or have owned.
Re. protecting the finish behind the bridge when changing strings, I always hold down a business card or similar object in place when I'm guiding the ball end through so it can't drag on the finish. I've started to do this on all of my basses, but it's especially important with the Moollons because the clearance for the ball end is pretty minimal. There's a similar issue with adjusting the truss rod. I basically just gave up on trying to protect the finish while adjusting it, as even with the proper tool it was almost impossible to avoid marring the finish. I've seen since that they offer a truss rod channel as an option - seems like that should be a standard feature.
I wish I had known that a truss rod channel was an option!
