dear

your graduation as well as your under graduation marks dont matter as such untill you sit for an interview ,as th interviewer might consider your post graduation marks

and as far as I know for general 

NLC have cutoff around 78

NTPC -65.93

for more information refer to the following link

https://engineering.careers360.com/articles/what-are-gate-scores-for-psu-recruitment

GOOD LUCK!