Deeds and instruments of writing for the conveyance of real estate shall be executed in the presence of two (2) disinterested witnesses or, in default thereof, shall be acknowledged by the grantor in the presence of two (2) such witnesses, who shall then subscribe the deed or instrument in writing for the conveyance of the real estate. When the witnesses do not subscribe the deed or instrument of writing as described in this section at the time of the execution thereof, the date of their subscribing it shall be stated with their signatures.