a copy of the Merlin Archive on this vehicle posted by sirhc confirms it was rebuilt. On 15/08/2013 it was at Witham (Specialist Vehicles) Ltd. However, the next entry reads "Date Not Recorded - RHG/D LAD". So at some point it was cast, but within the last nine years it has been taken back on strength, and has actually gone back to the Blues and Royals (Royal Horse Guards and 1st Dragoons). Is it still serving with them?
that’s not what it means at all, it just means no date was recorded for that entry. It will be in private hands or scrapped.