Calibra model name/ type approval number on VIN tag

[willie]

Can anyone shed some light on this for me?
On the VIN tag of my Calibra, the manufacturer is Adam Opel AG and the model name/ type approval number is 03807T.
I've seen Opel Calibras with the same manufacturer but with Calibra A as the model name / Type Approval number.
I had thought that because my Calibra is a DTM that it has a type approval number and that normal Calibras were described as Calibra A.
That was until today when I went to look at a '93 Vauxhall Calibra 16v and it had the same type approval number as mine and was built by Adam Opel AG. I also became a little suspicious when the guy selling the car mentioned that the log book for the car stated it was white even though the car was silver and had no evidence of being resprayed.
Can anyone explain the different descriptions??
Cheers