Gift deed for money given to adult sister last year

I had made a gift of money (via cheque) to my sister in last financial year (FY 2023-24) of 50 Lakhs (in Dec 2023 for purchase of apartment). I had not made a gift deed at that time and I would like to know if I can now make a gift deed on stamp paper for the same now (to avoid any confusion / questions later on)?

If yes will it be a problem that the gift deed on stamp paper (100 Rs.) has different date than the date of the cheque / transaction when I gifted the money?

Thanking you.