I have been searching for quite some time for a 577-450 Martini rifle in shootable condition that I could afford and have finally acquired one.  Since I am totally ignorant on the history of these I am requesting help . I dont understand the different Mk numbers and since I cant find any such markings on this rifle I will describe  the markings I can read. 
  There are no visible markings on the barrel.  The left side receiver flat has some small marking at top left but it is illegible.  The only legible marking on the left receiver under the small illegible mark is the number 775
   One the right side receiver flat top center is a crown then under that V. R. then under that Enfield then under that 1887 then under that some kind of heart shaped symbol with a star at the top.  Then farther down by a screw head the letters E. Y.  That is all the markings I can find on the rifle.  If anyone can use those to tell me anything about what vintage this rifle I would greatly appreciate hearing from you.  Many thanks !

No Sir I did not look under the wood.  It does have other markings on the stock. There are some numbers stamped as well as an Enfield stamp.  I also noticed that this rifle does not have the little thumb print thingy at the top rear of the receiver as I have seen on some rifles.  It has really weird rifling too.

In giving it a good cleaning I dont notice any change in the feel of the tight patch going through the bore.   
I did take the fore end wood off and see a bunch or writing on the bottom of the barrel.  I will need to give that area a good cleaning then get good light on it and a magnifier and try to read it.