the "LAST hemi'cuda" is BS23R1B429180 & sold at a MECUM auction in INDY 2011.

based on my research & in my OPINION: the 'Cuda was built 5,000+ cars before the subject HEMI Challenger R/T (JS23R1B43xxxx).

it appears assembly line #2 was running 2 assembly shifts during June of '71 when these two cars were built. I don't have enough info on '71 HAMTRAMCK at this time (working on it, but '70 HAMTRAMCK line #2 was building ~1100 cars per day in June)

the two HEMI e-bodies were "SCHEDULED" two days apart: BS23R1 on Monday June 14 VS. JS23R1 on Wednesday June 16, but IMO they were built closer to 5 days apart with the 'Cuda being built first.