Hello, 

As per your question, i would say that you have been selected for a seat in medical college. So after counseling, you will be given provisional allotment- letter which will be verified with your documents than you will get final allotment- letter. 

Basically,It is the same allotment letter which you get after the result of choice filling(counseling).It enables you to take admission in your provisionally (temporarily) alloted college.All the admissions are kept provisional for some time, so as to check all the details provided by the candidate and after verification and submission of fee, you admission become permanent. 

Then after all verification and confirmation, you will get the final letter for your admission.

For more information please check into-

https://medicine.careers360.com/articles/neet-seat-allotment

Good luck