Yes, I agree, noting that this requirement is for a latest FAR Par 23 certified plane, but is not a requirement for a CAR 3 or older 23.1581. CAR 3.777 makes no mention of IAS/CAS. CAR 3.778(a) also makes no mention, though points you to 3.757, which refers to TAS (just add to the confusion, I suppose!). 23.1581 does not seem to mention IAS until revision 23-50 of 1996. So any plane certified prior to that would not have to comply
Your ability to track down the various iterations of the regs is impressive. Incidentally, those extracts from POHs I pasted above are both from the '70s. As regs do change over time, the general advice, as ever, has to be 'consult your AFM'.