Be sure the confirmation of sales validity that is not more than a month, and subjected to approval of buyer loan, aka if the buyer fails to secure a loan, then the confirmation of sales become invalid.

Normally, loan approval processing won't be more than a month, whereby whether the loan is approved or not already known.

Confirmation of sales /= SnP.

Normally, banks do ask for confirmation of sales or 1% deposit receipt etc documents, to show buyer legitimate interest on the property.