Hii aspirant..

Since  you  have not given the wbjee examinations and have applied through JEE mains seat then you have to submit your rank card of JEE mains admission at reporting centres.

In the wbjee counselling seats are allotted  through both JEE mains rank and through WBJEE rank and if any seat is alloted to you through JEE mains rank then you have to submit rank card and other documents of your JEE mains exam.

So better you keep in hand your JEE mains rank card while reporting at the reporting centres.

Hope it helps.

Best of luck for your future.