What is interesting in the photograph is that it shows that the tank PREVIOUSLY had a wartine 'census' number, commencing T followed by its serial number, such as T-123456 for a tank. Immediately after the war the Army started to classify all of theirt vehicles and disposed of zillions. Those that remained were given NEW numbers, commencing with 00 RA- 01 and so on, up to 99ZZ99. These vehicles were all known as PRE-census vehicles, as in x9ZV29 above. I had another such vehicle issued to me, a Bedford QL workshop lorry, 77YC16. Those vehicles supplied AFTER the war were given registration numbers beginning 00BA01 (XXaa01 to 99AZ99 were reserved for the RAF). So all POST war supplied vehicles were in the B series onwards. My Land-Rover was 35CL21 and my old ARV was 33BA39.
There were a few anomlies too. For example, some of the older and upgraded Centurions had old wartme census numbers which were changed to the pre census numbering system, for example 17ZR 82 and later Centurions came with later POST war numbers such as 05BD90 or 16BA61
Simple 'eh! It was an easy way of telling what vehicles were old and which vehicles were REALLY old....., wartime old, such as the Diamond T's and Churchill bridgelayers and ARV's and Dukw's..... all with YP numbers such as 66YP04. Jeeps were all XXYHXX