I take your word that you have seen it, although I can imagine the warranty nightmares it could lead to for manufacturers. Do you think the Bose 301 would display such a harmful impedance?
I have no idea, as Bose never publish specs. But in the manual it says the amp has to be four ohm capable. There are two woofers, both different and three tweeters, one different.
So you know the speaker is going to be around four ohms. Since the speaker like all Bose products will be a total mess, Heaven knows what the phase angles are.
A receiver of the vintage the OP has would not like anything less than eight ohms and if the phase angle goes anywhere into positive territory, which is highly likely, then blowing a receiver like that is pretty much a certainty.
Unfortunately few speaker manufacturers are honest about impedance ratings and the phase angles are seldom mentioned. Most speakers are in fact four ohm these days no matter what the manufacturer says. These days you should never select a receiver or amp that is not highly four ohm capable, or it will have a short life with a lot of speakers.
Here is an ATC bookshelf speaker, which is excellent and in my view comes from a series of bookshelf speakers that are right at the front of the pack.
Now if you look at the impedance curves it can honestly be represented as a a 6 to 8 ohm speaker. However look at how far the phase angles go into positive territory. This speaker will seem like almost a dead short at certain frequency. For this series of speakers, robust powerful amplifiers have been found to be mandatory.
Now when you design a speaker you have to take the impedance curve and phase angles you get. Smooth response must trump everything.
Now the late Peter Walker founder of Quad maintained that any self respecting amplifier must be stable into all loads. His were, few others are. That probably goes a long way to explain the extreme longevity of his amplifier designs.
In other words, it is the amplifier designer's responsibility to build amplifiers that will drive any speaker, not the speaker designer's responsibility not to blow amplifiers.