I know it's a long shot, but... Can be either with or without (older style) the central Omega symbol. The photo below is an example off the 'net. Thanks, Adam
Not mine. https://www.ebay.com/itm/Vintage-Om...YAAOSwEP9cfYlk&LH_BIN=1&LH_ItemCondition=3000Purchases made through these links may earn this site a commission from the eBay Partner Network
Saw the above too late, alas, but found another (similar to my sample pic above), thanks to a new OF member.