Eric, thank you for your reply. My friend John B. Egan passed away one year ago at age 82. The railroad was his life - 40 years with the Grand Trunk and an overlapping 40 years with the Conway Scenic. He was quite well known in the New England railroading community. We do not know where he found this lantern, but, since John's extensive collection of lanterns, books, locks, keys, model rr locomotives/cars, etc., were pretty much New England/Northeastern US related, I would expect this lantern to be from a geographic area John frequented. No only that, our line of thinking is that because John was extraodinarily picky about his RR "stuff" he probably would not have kept a lantern in this condition unless he knew it was rare.
I am attaching 2 more photos, please let us know if you wish to see more pictures. We can send them email with higher resolution. Also can you tell us what other Railroads carry the designation MRR? We would like to research further.
Thank you again,
Ken