Actually, if historical production schedules are anything to go by?
You are likely to see the 'mass produced' ships, the small ships, to get regular design updates and irregular complete redesigns of the types of ships. Because these ships are produced in large enough numbers that such a standardized design is desirable and it's practical to update regularly. The medium size ships? That's the point where an entire class is designed and allocated all at once. Sure the entire class is standardized, and given the time it takes to go from design to ship if the entire class doesn't get constructed at once (it won't be) you're likely to see new builds using refined designs and newer equipment while their older siblings languish with older stuff until a fleet wide update program.
But the big ships?
Big ships are bespoke. All of them. The US build ten of its Nimitz class carriers, but it took from 1968 to 2006 to build all of them. Which means that basically every time a carrier was getting build the US had the time to look at what was working, what was not and redesigning and refining the Nimitz class with every new ship. You could make a decent argument that calling it the Nimitz class is mistaken as each ship could be considered a subclass of the design by the time the keels got laid down.
There's a point in production, especially when the R&D cycle is running fast, where creating a factory for serial production optimization is not profitable, because it takes too long to build even a single item to even consider producing a second with the same setup when it's already obsolete.