I'm with you on this one - the front end says TE-21 to me, not TD-21. However, the Alvis Owner's Club keeps pretty good records, and the listings are submitted by the owners of the cars - and I would think that they would know what they have. Also, the shipping date for the chassis is listed there as January 1963, and I have often wondered how long it took Graber to actually complete and deliver the car . . . perhaps it was into 1964? In any case, a 4-door 3-litre Alvis TD-anything is pretty rare. It's a lovely car, and a great puzzle choice. I think both of us would appreciate anyone with further documented information on this car adding it here.
And thanks for the point - it's difficult when there is conflicting or unclear information about the puzzle car, and in the end, it's your puzzle and your call.