Hello Gene,
It looks like a genuine New Model Army to me. There were three barrel addresses used on the NMA’s. The early one was a two-line address:
PATENTED SEPT. 14, 1858 / E. REMINGTON & SONS, ILLION, NEW YORK, U.S.A. The second one had the words NEW-MODEL stamped between the two line address and the frame. The latest was a three-line address: PATENTED SEPT. 14, 1858 / E. REMINGTON & SONS, ILLION, NEW YORK, U.S.A. / NEW-MODEL. Just to confuse things it could also be a transitional revolver with an Old Model barrel. That address would be, PATENTED DEC.17 1861/MANUFACTURED BY REMINGTONS’ ILLION, N.Y.
As you can see none of these seem to match the letters you have deciphered on your revolver. Does your revolver have any inspector letters on any of the parts? Does the serial number on the bottom of the barrel and the left grip frame match? I suspect it may be a civilian revolver which may have had a dedication engraved on the barrel.
Hope this helps
Bill