Hi Richie,

Here's the list (from Janice O'Neal's list):

FM - Franklin Mint
CC - Continental Coin
CM - Columbia Mint
SSM - Silver State Mint
USM - United Silver Mint
HH - Hoffman & Hoffman
RW or RWM - Roger Williams Mint
J or JM - Jani Mint
OPM - Olde Philadelphia Mint
NCM - Nevada Coin Mart (also Nevada Coin Minting)
CT - Casino Tokens N. Las Vegas
GD - Green Duck
GDC - Also Green Duck Corporation
LM - Letcher Mint (Also Lancaster Mint)
G - Global Minting
OC - Osborne Coinage
S - Sunshine Mint

Hope this helps!

Roy Baldwin
R-4155