John, go to the main PGCA web page
www.parkerguns.org and on the left side is a list which are in fact links to other pages. Click on and read over the "Parker Identification" and the "Grades" pages and see if you can ID the grade of the gun.... Assuming it is a Parker Bros. gun.
Read the "Parker FAQ" link too, there is some good information in there that may help you learn about your gun.