There have been 2 versions of the TT logo on the back of the Audi TT 8N over time. This for keen viewers.

Until September 2002
In the early years of the TT, the logo was with flat silver letters that were matt/brushed. The part number of this is 8N0 853 743B.

From September 2002
In the middle of the TT's life cycle, the logo had a restyling. From then on, the logo was imposed a bit higher with shiny silver letters. The part number of this is 8N0 853 743C.

Inspiration for the logo
The inspiration for the logo is quite obvious if you add the NSU TT logo. And quite logical if we know where the name came from (see an earlier topic ‘Where does the name TT come from’)