Re: 3 Registries for the Yamato?
The Stargazer had some similar problems. The filming model has the registry of 2893, and I think IIRC FASA also used a 2800 class series for their RPG list. The model in Picard's ready room however has 7100 and this number showed up in some other sources that represented the ship. It's just another behind the scenes goof.
"If you think you're brave enough to walk the path of honor, then follow me into the dragon's den."