Apartment Details not Mentioned in Agreement for Sale

Dear Sir/Madam, I am planning to purchase an under-construction apartment in a project by a builder in Kolkata, West Bengal. As per RERA, the builder has sent me an agreement for sale which I need to sign and register before the sub-registrar. I have 2 concerns about the content of the agreement: 1. When describing the property being allotted, they have just mentioned the carpet, built-up, and super built-up area (which is as per the promise made), but they haven't written the number of bedrooms, toilets, living room, balcony and kitchen. They have only sent me a brochure that mentions it is a 3BHK+3T, which won't stand before a court of law. 2. One of the builder's subsidiaries owns a commercial property next to the residential property they are selling me. Now the car parking they are offering me is inside the commercial property and they are executing a separate agreement for sale for that. I wish to ask: is #1 an accepted format because if they do not write the details can they change a 3BHK to a 2BHK later on? And for #2 can there be any legal hurdles in owning and selling in future or any issues with property taxes?