Gstr 3B wrongly filed

Correction is not Available.

So consider those invoices in March.

To be on safe side write a letter to your local GST officer explaining the facts to waive interest

Can't we pay the same through Drc 03 ?

DRC-03 is a payment form in which a taxpayer can pay the tax by raising its liability voluntarily or in response to the show cause notice (SCN) raised by the Department..

Since you are filing GSTR-1 quarterly, GST dept don't trouble you , they check quarterly reconciliation..

But buyer may ask for payment confirmation..Even if you pay , the buyer can avail ITC in March only since you upload all invoices in March GSTR-1

Yes as said payment through DRC 03 can be made voluntarily right. So would it be correct if I voluntarily pay the amount missed to be shown in Gstr3B. Also as payment is made within due date would it attract interest then.

No...
DRC-03 form not required in Your case. You can rectify the mistake through March month GSTR 3B return.

Pay with interest for the missed bills value...