As has been said, I think you no doubt have a pair of original vintage Ones and mistakenly consulted the BB value of the 'reissues', which were -- general design principles and inpiration aside -- completely different speakers made by a different company that bought the Allison name, and which retailed for several times more. (Jaybo would be the expert in that comparison. Both companies are defunct now.)
I've owned two pairs of the originals, the second of which I inherited from my father (actually, that set was comprised of a One on a flat wall combined with a Three in a corner -- an arrangement suggested for his particular room layout by none other than Roy Allison himself, a corner-loaded Three being the functional equivalent of a One on a wall). If I had the space and the inclination to collect vintage speakers, I'd have a set still. In audiophile terms they are at a disadvantage against modern speakers when it comes to all those speaker bugaboos that have largely been tamed since the 70's, like coloration/distortion/resonance/resolution. But in terms of sheer listening involvement they remain better than most, due to Allison's advanced design concepts for successfully addressing dispersion and room-interaction effects that he first identified and described (concerning woofer-loading and midrange cancellation, which are still largely ignored in speaker design to this day despite being universally recognized as empirically valid).
I would advise against replacing the tweeters unless you have to. Of course modern tweeters can go higher cleaner than the paper originals, but none have the idiosyncratic Allison 'split nipple' design which gave them an unusually broad power response designed to complement their 45-degree lateral mounting orientation, and Ones would not sound like Ones with conventional pistonic tweeters. Same for the dome midranges -- if you want modern sound you'll need modern speakers, but enjoy these for themselves. And make sure whoever reconditions your woofers has familiarity with the intended mass/compliance tuning of the acoustic-suspension originals, which used heavily (and heavy!) doped cones unlike typical modern light-coned woofers.
(And go very easy when fitting the still-ahead of their time, acoustically transparent one-piece frameless grilles, which become less flexable as they age and prone to cracking.)
