That is all the info Albert's had. This is part of his explanation of Relative Values: The letters "RV" are used to indicate the relative value of a button. This estimated value is based on buttons in fine condition and takes in to account the present scarcity and demand, as well as current prices in different parts of the country. Badly worn, damaged or excavated specimens have less value. Further note that the "RV" is not an indication of any specific dollar value and that unususal demand or the finding of unreported collections will affect relative values.
Remember, this book was published in 1977 so values listed in it probably do not reflect current values.
The following info comes from "American Military Button Makers and Dealers; Their Backmarks and Dates" by William F. McGuinn and Bruce Bazelon.
George Armitage, Phila., Race St. Armitage was a plate worker from Sheffield, England who appeared in Philadelphia in 1795. The first confirmed date of his making military trimmings is 1798. His button-making dates are from 1799-1826. Infantry buttons marked "Eagle Factory" alao were made by Armitage, c.1815-1821. Armitage produced a die for artillery buttons in 1804,1806 & 1821; infantry buttons in 1806,1810,1816,1818,1821 &1826; rifleman buttons in 1808 & 1811; & "US" buttons in 1826.
The backmarks on your button should read either "Armitage/Philv(sic)" GI-74A2 or "Armitage/Phia" GI-74A1.
So your button was probably made between 1806 and 1826. As far as monetary value, I couldn't even guess. I will say that the "RV" at 10 is not very rare as there are buttons in Alberts book from the same period with "RVs" of 45 and higher.