A 69 is NOT a Duetto!
I have said it before, and I will say it again, a 1669 roundtail is not a Duetto. It is a 1750 Spider! A Duetto is a 1600 roundtail with Webers produced in 1966 to 1967.
That being said, I would not pay the reserve of $31K for this car because it is not original. I have nothing against period modifications, but the foglights, number decals, etc. detract from the car. It is "over the top" as far as I'm concerned.
That being said, I wish the seller luck. He may happen upon someone that really thinks this car is what he wants and is willing to pay the price. (at the time I write this, there are no bids, thank God!). To the potential bidders, I say "buyer beware!" Check out other listings and get a feel for the market for these cars. Only then will they be able to determine if they want to meet the seller's price. They could purchase a lot of nicer examples of roundtails (whether Duettos or 1750 Spiders) at a much lower price.