Terminal Services in NT4 was a seperate and distinct product
- so called Windows NT4.0 - Terminal Server Edition - which is why some folks still call WTS, "TSE" from the abbreviation.

As this was a complete new OS, with seperate disks, no, there is no easy way to upgrade a NT4.0 system to NT4.0-TSE.

Yes I agree Terminal Services in W2K is much better than anything else.
However, NT4.0 TSE is not as good - it has limitations that W2K Terminal Services doesn't.