Basement finished without permits

[Shiri Manor Nisenbaum]

I am looking at a house on Atlanta in Rockdale county. Tax record shows its 3+2 .The seller build in the basement additional 2 + 1.

The property manager say we can get rent for 5 rooms, which is much higher. Renters dont care from tax records that shows there are only 3 rooms

Wont I have a problem to sell it?

What is the ARV of such house according to 3 or 5 rooms?

Thanks, Shiri