Bedroom conversion without permits. Buy or not buy?

[Charles Situ]

I am considering purchasing a duplex with 3 bedrooms on each side from a wholesaler. The seller is flipper that converted what was enclosed porch areas to a bedrooms by removing double sliding doors and enclosing it with walls, and also added closets. I checked with the county and they do not see any permits. Seller & wholesaler says that since the layout was not changed, they don't need a permit. I am worry that the conversion is not to code and that the city may tell me to convert it back while I have tenants in it. Or maybe city has no issues with it, but I can't market it as a 3-bedroom if I need to re-sell and it may prevent me from obtaining a higher price. Should I buy or walk?