My apologies. I should have looked at more sources before posing my questions.
Apparently the rarity is supported by a relatively low block of P-51k production. Please correct me if this is an incorrect assumption.
Joe Baugher's site provides the following information:
Quote:
The Dallas plant also built 1500 P-51Ks, which differed from the P-51D in having an 11-foot diameter Aeroproducts propeller in place of the 11 feet 2 inch diameter Hamilton Standard unit. These were all known as NA-111 by the company. The P-51K had a slightly inferior performance to that of the P-51D. Rocket stubs were introduced on the -10-NT and subsequent batches of the K production line at Dallas.
A total of 163 of these P-51Ks were completed as F-6K photo-reconnaissance aircraft. 126 Inglewood-built P-51Ds from blocks 20, 25, and 30 were converted after completion as F-6Ds. A few others were similarly converted near the end of the war. All of these photographic Mustangs carried two cameras in the rear fuselage, usually a K17 and a K22, one looking out almost horizontally off to the left and the other one down below looking out at at an oblique angle. Most F-6Ds and Ks carried a direction- finding receiver, serviced by a rotating loop antenna mounted just ahead of the dorsal fin. Most F-6Ds and Ks retained their armament.
regards,
t~