Antique rare mezzotint 1903 or earlier not reprint William 2nd of orange/holland

I've done as much research as I can on this artwork this is numbered #6 photo gravure bottom left also has name of subject bottom right have to remove art work from frame to see. Has the frame shop that framed it tag on back behind paper took forever but finally found out they were in business early 1900s found receipts for actual store in Baltimore Maryland with same address on label shows dates of 1903 receipts not of this item but shows what year they were opened to date this artwork roughly. I looked at art with jewelry loop make sure it's not printed was upset because definatley thought it was if you look close magnified can see dots like digital print. Its not it's a mezzotint can feel raised art on paper from pressing of copper plate also frame and paper are easily 100 years old look up process to much to explain limited to what can describe almost out of room pic is 11.25 in.wide by 19.75 in.tall frame 19.25 w 22.5 in.tall found one close on ebay no # or signature smaller size