Kolkata Medical College is a Government Medical College. And so, 15% of the seats are filled through All India Counselling and the rest 85% of the seats are filled through State Counselling. You haven't mentioned your Category. Nevertheless, in 2019, under State Quota, the cut offs for various Categories for Kolkata Medical College have been as follows:

General Category: 614

OBC: 606

SC: 523

ST: 352

Under All India Counselling, here are the cut offs:

General Category: 640

SC: 584

ST: 511

Now this is 2019 data and cut offs change every year. Cut offs change every year depending on various factors such as no.of Candidates appearing for the exam, no.of Candidates qualified, top NEET score and difficulty of the exam. So for a seat in this College, you should aim for atleast 50 marks more than those mentioned against your Category. This time as NEET has been pushed back by 5 months, Candidates have had time to prepare and so the cut offs are expected to be higher. So atleast 50 marks more than those mentioned against your Category should be your target.