Need to find roof/plumbing/wiring age

[Mayank S.]

I am recently under contract to buy my first multi family and going through due diligence phase. After contacting with my insurance agent to include this one in my existing policy which has few more single family properties and a blanket liability insurance, the insurance carrier (Indiana farmers mutual insurance) would need the last upgraded time or age for plumbing/roof/wiring to include it with other property insurance or to issue a separate policy. Now the problem is property is through MLS and seller also being an investor have no clue about their upgrades. I have got the inspection done and all three components (rof/wiring/plumbing) are in decent condition and functional but no idea when was it upgraded. Inspector can only guess estimate the age.

Seller has addressed few items related to plumbing (leaks), roof (replacing some shingles) and I have reinspection scheduled for tomorrow. Now my question is what and how can I provide the estimated age or last upgrade time of those components. In case of any incident related to roof or something, can insurance company deny the claim stating the age stated was not correct or something? Need some opinions and Thanks in advance for your response.