Bowdoc has it right. In addition, and this applies to 1959 and 1960 Grizzlies only; serial nos prior to FK are 1959. This is based on 35 1959 and 1960 Grizzlies that I was luck enough to view, most of which I fondled.
Coins varied, most were Brass and some were German Silver(like 1960 Kodiak), one was aluminum and another copper; and the last two could have been replacements along the way. I would love to compare results with others if you have kept notes.