Do they currently own this apartment and land, or are they renting this apartment and have decided to purchase the property to build on.
If they currently own the apartment and land, then ROR applies. If they are renting, and have decided to purchase the property then ROR would not apply IMO. However, if they are purchasing the property on contract and are paying off the contract and getting the const/perm loan, ROR would apply.
The opinions expressed are mine and they are not to be taken as legal advice.