by Mike –
More than one GT40 for sale in the same magazine! Even in 1971 a used Ford GT 40 was $15,000, however, it still would have been a great investment.
These classified ads are from the April 1971 issue of Road & Track.
The advertisements below are from the same magazine. Remember the Pinto? I have not seen one for many years.
I had forgotten that the Vega was the Car of the Year. Again, I have not seen one for many years.
Let us know what you think in the Comments.
Summary

The GT40s always get a lot of attention as well as being a target for replicars (I recall the FiberFab Avenger among many) but your listing of a Mk IV is unusual. I haven't seen any in vintage racing nor any special focus on the Mk IVs since then. I wonder how many survived? Where are they?
According to Wikipedia only 6 Mk IVs were made. It would be great to see one racing again.
Now that you mention Fiberfab, I plan to write about kit cars in the future.
Also, notice that the seller is the same for both GT40 ads.
The attached picture is an original GT40 in a slalom race driven by Harry Hienl whom lived about 4 blocks from my parents in Miami Lakes, FL. I took this picture sometime in the early 70’s. I wish I had bout one back then for $15K. He had the one with the bubble on top for I believe Dan Gurney. His wife would drive it on Sunday mornings to the grocery store. If I was outside I could hear it start up.
I grew up in Berkley, MI a suburb of Detroit.One of my neighbors was a Ford engineer. He bought two GT40s from Ford but having a one car garage couldn’t store them very well. i believe he sold them and later got a more practical Pantera. Let’s see, on 2022 prices, what’s a genuine GT40 worth compared to a Pantera….