Here is a view of the base. "H.G.CO" is embossed centered across the middle of the base.

Another specimen was also pictured in the November 2002 issue of Crown Jewels of the Wire, an article by Roger Lucas entitled "I Really Go for Go-Withs".

https://www.cjow.com/archive/article.php?month=11&a=11I%20Really%20Go%20for%20Go%20Withs.htm&year=2002