Just some notes and errata, sorry to be so tardy in posting.
The AA and RDL lines actually sold a fair amount of product over their lifespans, especially after CU (and many other mags) raved about the Six, CD6, and S1. The reason they do not show up used so often is that owners keep and like them. They do sound better --- especially when placed such that the woofers face each other --- than other 2-ways, by a margin.
So did, for a while, AA with the original Ones (and to a lesser extent the Two and Threes). The Fours were always a seriously big seller. Someone should revive the Four even w conventional drivers. What sound.
The shiny sticky layer was added to preserve driver and surround longevity, and dust and crud and dog hair settled thereupon make zero sonic difference. I would never spend time scrubbing them clean, if only for fear of damaging or offcentering the voicecoil (or harming surround or spyder).
The drivers in the RDL and the AA and LC lines are all identical; actually, there may be slight variances in the 8" woofers, adaptive to cabinet volume, details about which are available in the Allison io (google) group and possibly in the new Facebook group (I am trying to get them to overlap, of course).
The newer 'nipple' tweeters (RDL) do not have stranded-lead corrosion problems, I believe, as in some earlier AA models. Even better, Kentucky used the original tweeter design, not OEM, for all Allison-branded designs, and in fact their manufacturer poor Eminence laboriously and nontrivially improved on it, a simply remarkable achievement, given what a complete bear it is to manufacture. (I cannot get OEMs to even look at it.)
The RDL lines is identical to the AA CD5, 6, and 7, and those were improved over their originals only (or at least chiefly) from having a steeper highpass (12dB) to the tweeter, to protect it in the new digital era back when. The difference b/w the B1 and the FS1 (hope I have it right) is solely the VLF reach, similar to the diff b/w the Six and the Five/Seven or b/w the LC120 and LC110, the latter of which must be the best-performing wideband cheapy in history.
Anyway, if you have not done so already, I urge joining the Fb and io Allison groups. More info than you'll ever need, probably. I just uploaded an ESW schematic that came into my possession, the only one uncovered ever. Its designer Mark Davis (dbx Soundfield, Dolby AC3, and much more) could not believe how complex and rich it was ....