Hey Bonk, when I ran the uninstall it didn't restore my previous shiplist/fighterlist. Was it supposed to?
It will restore whatever shiplist and fighterlist, strings and textures you had when you installed SFB-OP, I have swapped between it and OP+ many times no problem. I used to include stock files in my installer to restore on uninstall, but because of download size pressure I went with the strategy of backing up whatever shiplist was present when SFB-OP is installed. It is possible if you install SFB-OP over itself, without first uninstalling, it will back up the current shiplist to restore, which is the sfb-op shiplist... All my installers now check to see if the mod is already installed and refuse to install if it is already present or if a previous version is present. I apologise for not thinking to include this in SFB-OP-04, it will be in the next version, so that you cannot accidentially install it over itself, thus backing up the mod for restoration instead of previous files. It sounds like this is what you have done.
Let me know if you need any stock/OP+ files, I can zip em up and pass em on. (edit: a set of stock files to restore from sfb-op is attached below - my current installer created backup folder...)
Also, for reference, the NSIS installer scripts for SFB-OP and the newer KCW installer (with over-installation protection) are attached for comparison.