Framed 19th c. ambrotype signed and numbered 17/27!

I picked this up last weekend at a yard sale for $6.00. I thought at first it was a lithograph but after I got home I was pleasantly surprised to find out it was actually an ambrotype picture that was later framed around the late 1800's early 1900's color and the moon was added by placing moss green color backing with a painted moon. I cant make out the artist or photographer but it is numbered 17/27 and there stamp from RM manufacturing with probably sold the item or something. I am stumped! So I will continue to research until I find out all I can about this piece. Ambrotypes were produced from 1855 to 1865 then replaced by the daguerreotype. I just enjoy it I have never owned a piece like this. it would be nice to find out where it was taken and if there are similar pieces by the person who signed this and an exact date...