There are a handfull of '72 440+6 (Road Runner/GTX? & Charger Rallye) cars known & probably another handfull dead & gone. There has been a couple good threads recently on the subject -
here's one of them.
WAG - Chrysler Corp. ordered '72 spec'd & number'd 440+6 carbs from Holley & recieved some before/during/after cancelling the program. Carbs in-stock at Chrysler were sold "over-the-counter" as parts.
2581 = 258th day of 1971 = Wednesday, September 15, 1971