Car parking sale deed

I am going to buy a flat in a society. The flat does not have any car parking with it. The current owner of the flat had purchased a car park from another owner X through a sale deed. In the car parking sale deed " The car park is included in schedule c of the property of owner x" and also it has been mentioned that owner x has agreed to sell only car parking component in their property" FYI The sale deed between owner x and the developer did not have car parking mentioned owner x has the allotment letter for the car park from the society. Now i need clarification 1) How the car parking no came in scheule c in the sale deed executed between owner x and the current owner of the flat which i am going to buy? Is it valid? 2) Can i include the car park details in the sale deed that i am going to execute with current owner of the flat which i am going to buy?