First NTSC Receiver 1941

[Penthode]

A question which has been lurking in the back of my mind for a long time is what was the first manufactured NTSC standard receiver?

The prewar receivers from 30 April, 1939 followed the RMA standard 441 line AM sound negative video modulation vestigial sideband video transmission. The standard 525 lines FM sound was adopted by the NTSC by April 1941 and authorized by the FCC July 1, 1941.

I have seen RCA TRK12's modified from 441 to 525 line video (change of horizontal sweep frequency from 13,230 to 15,750 Hz) and the use of slope detection from AM to FM audio demodulation. Were there any TRK12 or other receivers manufactured between April 1941 and 1945 with proper FM discriminator circuits specifically for the new NTSC Standard?

Of course Pearl Harbor in December 1941 put an effective halt on television. However Iwould have expected in the six months leading up to the US entry into WWII and prior to the unveiling of the RCA postwar 630TS an NTSC manufactured Television Receiver.