No, promotion registration dates are fixed and the list of items at the time of registration cut-off is what is reviewed by our teams internally. However, Seller Center may allow products to be added after the registration date. These are not reviewed and are not added to the final list of promotional products.
Please ensure that products are added before the registration date and avoid adding products in the last 30 minutes before the promotion as there is a lot of activity during this time and depending on the volume that requires processing, not all products may be added in time.