Jerom0621 ... Your question is valid.
I have never owned a pickup before, and my research was done on Craigslist.
I found that the 7.3 engines included the term TURBO DIESEL and the 6.0 engines ( typically )just said " 6.0 diesel ". It was my assumption that ONLY 7.3 were TD's.
When I saw TD on the side of the truck ... and had been advised by a friend ( rather Ill-Advised ) that 2003 was the last year of the 7.3 ... I looked no deeper.
This is a mistake that I will regret for a long time ... I suspect .
I still see no BIG 6.0 plate ... I discovered it by virtue of the owners manual that said it.
Richard