The NX-01 isn't on there because it didn't exist when ST:TMP was made.Well if the NX-01 could be left off the TMP wall,
When a new production introduces a "Pretend this always existed/happened. **WINK**" type thing... said thing doesn't magically appear or get referenced to in stuff made prior to its introduction. You instead have a pre-thing and post-thing continuity point.
i.e. Thing only exists in stuff made after its creation.
There's no NX-01 Enterprise reference in ST:TMP because it's pre-Enterprise.