Is it normal to ask a seller to provide an itemized list of renovations?

Hi, all!

I am interested a two-family house that has a renovated basement being used (illegally) as a third unit. The basement has undergone extensive renovations, including the addition of a small kitchen and bathroom as well as tiled floors. The two upstairs units have also gotten cosmetic renovations (eg, floors, bathroom, kitchens). Because the basement is not legally “livable space,” it has been excluded from the sq ft calculation, which is 1,672 sq ft.

The house sold in 2022 for $277k and is now being listed for $599k. I think that is overpriced given the fact that the legal livable space is 1,672 for a two-family, but the seller seems to be pricing in the basement renovations to the list price.

A key detail is that the house was built in 1897 and the only plumbing updates have been for the bathroom renovations in units 1 & 2 & basement. I’m also not sure of the ages of the electrical or heating units. The water heaters will need to be updated soon (one for each unit).

I was thinking about making an offer at $570k with flexibility to go higher if the seller provides an itemized list of renovations (including the basement) and/or if the seller’s agent provides comparable two-family sales in the area at 1,672 sqft.

Am I being too difficult? I like the house but not enough to pay for a +118% increase without proof.

Thanks!