I was given a Iver Johnson top break revolver by my Grandfather. Top of barrel reads "Iver Johnson's Arms & Cycle Works" 2nd line "FITCHBURG MASS. U.S.A" each line starts and ends with a star. Under left side grip stamped "77" also stamped "77" under trigger guard. It is nickel plated with pearl colored plastic? grips. Seems solid. Curious what year it was made and is it safe to shoot.