Did RCA use WB IQ after the CTC2/Bs.

[Tomcomm]

So far only the CTC 121 and CTC136B were suspected to have used WB IQ chroma demodulators. Wayne states he evaluated the performance of a RCA CTC13X that had WB IQ demodulators but gave no details of its implementation; did it use a NEC IC? A whole bunch of guys say they have or had either CTC 136Bs or the CTC121s which also is claimed to have WB IQ processing:
CTC136B stromberg67 Kevin
CTC121 zenithfan1 Mark, waltchan, zenith2134, wa2ise, nrx37, blast
Surely at least one of these has a schematic or other documentation that definitely proves the CTC136B or CTC121 used WB IQ and how it was implemented. Since I have a CTC2B open on the bench I would appreciate any information why RCA tried WB IQ on only a couple of CTVs and quickly dropped it. Thanks, Tom