Hardly. You will find such people in quite literally every part of India, doing low end jobs and speaking in a strange Bengali accept. Many with "hindu" names but when you check their mobile number with True caller, it shows up with a muslim name.
Catch hold of ANY beggar in Delhi or Kerala or any Hindu religious place and they will have an "bengali" accent but will claim to be from some other state in India.
Ask ANY Indian in pdf and he would have encountered at last 1 such person.
This is how Bangladesh manages to keep its population "under control" earning praises from the UN. lol.
India desperately needs a NRC.
Here is just one e.g. out of a million.
Adhaar Card says Name: Arjun
Real Name: Aarif-ul (Bangladeshi Infiltrator)