[ajmac]

As Adrian said the war department number, for anything tracked, the 'T' number, originated in England, when an order was placed a block of numbers was allocated to that contract, I have seen some of the Loyd Carrier contract cards held by the tank museum earlier in the year, there may be T16 cards too. What does nigels carrier book volume 2 say, his section on loyds in volume 1 has all the WD number lists for loyds.
The data plate would have had the WD number stamped on it as well as a vehicle serial number which was unique to the manufacturer, the T16 parts book refers to change points using the vehicle serial number. It goes on to say:
vehicle serial numbers were first assigned to each hull when fabricated rather than the final assembled vehicle, this number prefixed by FS should be stamped on the transmission and final drive housing. After hull number 1000 the vehicles were assigned a serial number without prefix or suffix, it was stamped on the top upper right hand front plate also transmission case and final drive. So you should be able to have a stab at your vehicle serial number my havin a look in these places...obviously be careful of parts that may have been replaced in service.

I presume the TD part is perhaps a corruption of the T number, I have seen a Loyd data plate stamped CTxxxx, which doesn't exist in the wartime contract cards, however the vehicle fitted the bill for being the number without the C. Like all of these things not as black and White as it first seems :-)