Well, heck. Thanks so much for the info, all. It certainly seems to fit. The cabinets have no visible butt joints, so veneer makes sense. Also, while the grain does not resemble what is currently available as "rosewood" in the audio and furniture markets, it also does not look like walnut, birch or any domestic species.
I assume that the close graining that is typical of current rosewood products is a result of harvesting managed growth (which would be young and close-grained). These show large swirls, and wide grain. Satin laquer sounds right. Honestly, I had assumed that someone had polyurethaned them at some point, as the finish is quite hard and a bit shiny. Definitely not an oiled finish.
Also, thank you for the lead on the crossover upgrade/maintenance. I will follow up on that.
Finally, if these are of interest as a relative rarity, I am more than happy to take additional photos of whatever aspect of them interests you all. Just let me know what you would like, and I will post, email, or whatever is of the most use, additional photos.
Also, do you think it is possible that the label code actually reads "H - BRSL?" Alas, the top half of the second speaker's label is gone, so I cannot compare. It looks a little like a dash, no? So, distinguishing HBR from H-BR...maybe.
I guess I did come to the right place []
Regards,
Chris