MasterGwydion
Emperor Mongoose
For publishing convenience, yes. That is why using Mass as opposed to Volume is bad for deckplans. You can't represent Mass on a deckplan. You can represent Volume.Well... mostly it's for publishing convenience.
But there is a thing where mass production damps out the variations you get with hand built bespoke objects. Before mass production settled on a small number of general purpose hammers (claw, ball peen etc) *every* job had several specialist ones. Since it's almost as easy for a blacksmith to make one tool design as another and were mostly supplying local people they knew, the customer got what they ordered. Farriers got different hammers to carpenters who got different hammers to masons. It's a constant frustration for re-enactor types that themselves aren't blacksmiths, who pretty much have to modify store bought tools as best they can or put up with general use ones that aren't totally wrong.
There never was a mass produced warship - liberty ships probably came the closest, although they were freighters. Traveller ships seem more modular than mass produced, but it's not unlikely that most shipyards are building most standard ships with little scope to vary the build outside of standard options. The components are likely cranked out in bulk to average TL standard at the nearest high tech industrial hub and shipped in as required. That would be the way to interpret the LBB Book 2 method.
The NAVAL ships seem to have much shorter active service lives with more ship to ship variation.
Even in the published ship classes, you do see variations within a class. Kinunir, Leviathan and AHL cover an entire class in detail, and we have a good sampler for the Gazelles.