So if two ships are being constructed simultaneously (like the Olympic and the Titanic), they are both assigned "00" as a placeholder until NCC numbers are established for them? That is, there can be multiple 00s being built?
You mentioned that the construction work on 1701 might actually be "internal reconstruction and upgrades." If so, then 1700 might be undergoing similar "internal reconstruction and upgrade." If it's just having some reconstruction done, then it's not actually being built. So, it actually could have been built before 1701.
You're not really suggesting that "% Complete" actually means "% of vessel's shipbuilding complete" rather than "% of vessel's repairs complete," are you? You're just yanking our chain, right?