Vintage Gold Filled Tethered Pin Initial M Scottie Dog Uncas Manufacturing Co.

Dainty little brooch engraved letter M, with Scottie dog attached by a chain. Marked on back with an arrow through a U. I was told it was gold filled but I can’t find a mark anywhere so I’m not really sure. Pins measure about 3/4 x 1/2 inch, Scotty Dog is about 3/8 inch.