Gordon, respectfully, modern AR coatings are typically given way more gravitas than they deserve.
What matters most is optical quality of the objective. Period.
An old doublet refractor objective of long-focus, with a superior figure, will give better images than a modern long-focus objective of "acceptable" figure, even if the modern objective has state-of-the-art coatings.
We are talking about less than 15 percent throughput here, in most instances, for all four surfaces of a doublet. In my half-century of experience, fifteen percent brighter image at the eyepiece is nothing, compared to superior resolution.
It has been demonstrated that most observers cannot detect even a one-magnitude difference in image brightness, from the center to the edge of the field. The stellar magnitude scale is logarithmic, so, for example, a star that is midway between magnitude 2 and 4 is not magnitude 3, but closer to magnitude 2.8. So a magnitude difference of one is 2.512X brighter. A 15% brightness difference due to coatings is nearly negligible.
Coatings play a much more important role in modern multi-element eyepiece design, where there can be 6 or 8 air-to-glass surfaces. Throughput loss would reach 30% if not mitigated by AR coatings.
The Japanese post-war refractor industry has the advantage of having been taught the essentials of objective design by their WW2 German allies. It was Zeiss who taught the Japanese how to make essentially perfect refractor objectives, and the export industry after the war profited from it. Most (admittedly, there are exceptions) exporters produced refractors with excellent objectives, given the glass formulations of the day.
Having used a 9" Clark, as well as numerous modern refractors, it is my opinion that modern AR coatings are way overblown in their importance to perfect imagery.
The closest modern analogues to classic refractors would possibly be something by D&G, though they don't make small aperture objectives. Edmund still sells small-aperture refractor objectives, but the price for one lens would be considered very high in comparision to a used, classic Japanese refractor of similar aperture.