Thank you for providing well-focused closeup photos of your Virginia State Seal button's front and Griffith backmark. The confirm the time-dating information in the MGuinn-&-Bazelon book on backmarks, and the Albert book's classification of it aas being a post-civil-war button. It has the front shown as VA-24A1 in the Albert book. Also, the Griffith backmark is written in "plain block" lettering rather than "serifed" lettering. I know of only two button backmarks from the civil war era which are written in "plain block" lettering. It is a very nearly 100% accurate rule of thumb that the button was manufactured after the civil war ended.
For anybody who doesn't already know... "serifed" lettering has tiny prongs on the ends of the letters. (The prongs are called serifs.) See the diagram below, which shows the serifs in red. The words "United States of America" on a US dollar bill have serifs, and the word "Liberty" on a US penny is "plain block" lettering.