YS-715 is a black Yenko Camaro and is a known car.
Most of the found Yenkos have just the dash with no fleet code but some have the dash and the number and some have no dash or number.
Yenko had some cars drop shipped to St Louis rail yard for the Dick Harrell shop to convert but the NICB still comes back to Yenko Chevy.
This NICB comes back to Jackshaw Chevrolet so the car was probably shipped there and sold there.
Why it is on the Yenko 107 NHRA list and why it has a fleet code is a mystery but was probaly built around the same time as a batch of Yenko's cars. There are a bunch of red flags on the 107 NHRA list that show they were not all 427 converted Camaros. There may be more of them that were not even Yenko sold cars.
With only 1138 4K cars built, there were not many to go around and Yenko got about 50 so that may be another possible reason he had to do a special order. Also may have got a better price on them, which is somthing that Yenko always tried to do.