had asbestos in them during the 70's. You know all this depends on how eager the seller is to sell and what the market is like. If the house has been on the market for over 45 days and not sold, then maybe they are getting hungry and desperate. Are other bids on the house?
You know asbestos is a big red flag just like mold is. If that is asbestos, then who knows.
I would consider having the owner have the test done and at their expense. What is your plan of action if the shingles are asbestos? You know that the owners will say, I have been here for x years and this has not bothered me. They are right. Asbestos is only dangerous when airborne. But its a mess to have it cleaned up and removed. You got moon dressed people there with the stuff. Big costs in removal and haul off.