vintage tie Firestone 10 karat pin 1955 10 year pin possible white gold

My grandfather worked for over 20 years making tires in Reading, PA. In 1955 he received his 10 year pin. I may be a year or two off.... It says The metal arts co. inc. from rochester, NY and 10 karat. I guess it is white gold. the back of the pin is bronzey and you have to pull the backing in order to unclasp its grip. He never wore it and left it in the box. It has been dry and in a non-smoking home. It is 3/8th inch across. It is small, but a solid thick piece. A bit of history. Please ask any questions and I will do my best to answer.