Cleaning 2 Cave mirrors in the same afternoon is what I call a great day! Thank you for the additions Jim. And an early one as well. Nice! That will be the earliest 10" in the registry. I also show the Astronomical Society of Harrisburg as having M704954, a 10" Model C.
Any chance of pictures of the engraving on either of these, especially M-166?
I will try. It is very light. I missed it the first few times I looked at it. And yes, ASH owns 2 Cave scopes, a 12" and a 10". We used to have a 16", too, but that was replaced in the 90's.