Clay Tile roof approx. age?

Can anyone tell me if there is a good way to estimate the approx. age of a clay tile roof? I tried the county records office and there is no permit on file for a roof expected to have been installed 2-3 yrs. earlier. Imagine that.

I was asked to do an inspection, and provide some kind of verbiage to the effect that the roof appears to be in good condition and based on the information given me, 1-5 years old is a reasonable determination of age. I have a drone operator that can take photos and video, I thought this might help me take a good look at the valleys, and the flashing, etc…

Any help would be appreciated. It is so the home owner can look at another insurance carrier, they are asking for it.

I always suggest they stay where they are. Things never go good when they change and it always results in additional inspections at their costs. Funny talking people out of business but I try to help not just take all I can get when it will hurt them. Not saying anyone is. Except the insurance companies.