Dan it is entirely possible that the "universal" over the counter kit was used because of the low volume nature on this engine combination. A 427 Cobra with a single four , cast iron manifolds and rear exit exhaust is pretty rare! Obviously the 428 is more common , but still a small number.
SAI sourced all kinds of parts locally on their own from day one with CSX2000 in Dean Moon's shop. The 'stuff' sourced locally is the hardest to find now especially items that were custom ordered or sourced from small manufacturing companies that didn't survive past the 1970s.
The whole engine "thing" was a string of "rare" combinations. CSX32xx and CSX33xx cars did not get as many SAI changes or additions to engines as received from Ford as CSX31xx cars did. That doesn’t mean parts for the 4V fitted engines are easy to find.
Most CSX32xx and CSX3301, received 1966 428 PI engines for manual transmissions to which SAI added some 427 Cobra only goodies. Rare doesn’t describe some parts for those engines as manual transmission hot rod police cars must not have been real common.
I have not heard of a CSX32xx car getting any but during the CSX31xx time frame SAI did offer a under chassis header system. CSX3141 was fitted with a set and an automatic transmission so the headers were probably just barely squeezed in.