The worn label, somewhat dingy look to the grilles, and 15Ω rating is what's throwing me off. I know they're expensive speakers but I wouldn't expect to see those characteristics even in late-model used ones. I know the current Falcon reintroduction is 15Ω, but as costly.
I know that high impedance makes them aimed at the tube amp crowd. Since tube amps are a much higher impedance source this makes them more suitable. For solid state amps their 8 ohm power rating will be halved. Add that they are very insensitive.
I know for a fact that Raymond Cooke had a lot of input on these speakers, especially as they were the original manufacturers. He promulgated the impedance compensated crossover. That made sense for tubes, with those amps propensity to follow the impedance curve of a speaker. However these speakers have an impedance curve like the Alps.
So not the best for tubes or solid state.
Having said that a lot of us have heard those speakers, and they are pretty good especially for their day but not outstanding. The real issue is that these days with all the advantages we make a lot of speakers that are an awful lot worse and that is the disgrace.
I have to say though that even back in their heyday, I preferred my efforts though.