Seems most likely to be a Mr. George Richard Hunnewell. Looks like he owned a farm and ran a feed company for some time during the early 20th century. I found reference to a hang tag for a G. R. Hunnewell Fur Co, also out of Auburn. Corroborating that was an old postcard with a black and white image of a fireplace mantle full of fox furs located to the Hunnewell Farm in Auburn, ME. An archived blueprint also exists on the Maine memory network webpage of “an architecture commission for G. R. Hunnewell at an unknown address in Auburn, ME, 1906”. Quite a nice house for the time. I found this all to be very interesting since Auburn is my hometown. The internet is a funny place. Not the first time he has come up here:
https://parkerguns.org/forums/showthread.php?p=398685 .