In tip 619, we dealt with two issues concerning non-retail versions of Windows NT.
If you want to verify that you have the Retail version of Windows NT Server installed, run this batch script:
set /a NFR=0
for /f "Tokens=3 Delims=:" %%i in ('find /c /i "nfr10usr" %systemroot%\system32\*v.*') do set /a NFR=%%i
if %NFR% GTR 0 (echo Not For Resale 10 User version) else (echo Retail version)