Title Deed Clarification

I am planning to purchase plot at Hyderabad. When I checked the documents then I found that following: 1. Four old people executed GPA to a person A in the year 1983. Questions: a. When I check document ID then its mentioned as xxx/1983. Whereas, its being singed in the year 1985. Can this happen? b. This document is NOT available online. In other words, I am NOT able to see this document over electronic EC. Can this happen? 2. This PERSON A (GPA) developed the above land and sold Plot 5 and Plot 6 (part) to PERSON B in 1986. Question: 1. This document is available online (electronic EC) on Person B's Name. This is happy news. 2. In the sale deed, they have mentioned house number only. However, its a open plot. In other words, Plot nos and Survey Nos are NOT being mentioned. Is it ok to just have house no? 3. Under Vendor's information, ONLY GPA holders name is being mentioned. However, original owners name is NOWHERE mentioned. Is this OK? 4. Under Scheduled Property, Survey number is NOT mentioned. However, on the last page (Where a plot box with NORTH, SOUTH, EAST and WEST information is provided) of the Sale Deed, Survey no is being mentioned.