Attached are images of the HW and GS models from the 1935 Old Town catalog, courtesy of The Complete Old Town Canoe Campany Catalog Collection, 1901- 1993, available on CD from
http://www.wcha.org/catalog/ and
http://www.dragonflycanoe.com/cdrom.htm on the web.
I chose the '35 catalog because the text is the same for many years. The very early HWs and GSs will appear somewhat different from these... and the HW model disappears from the Old Town catalogs after 1953. So 1935 seemed a good, average year for comparison.
As you can see from the pictures, the HW has higher stems and more recurve. In profile pictures, it can be confused with the Otca-- but for the fact that the older Otcas have long decks with coaming. I mention this because some folks think of the Otca as "the pretty canoe"... and the HW is just as pretty.
Not that a GS isn't a pretty canoe... but it is a utility boat, and while the HW can be used for fishing, it's more of a pleasure craft. It looks nice in solid green, but wouldn't look silly painted like a courting canoe. It's my idea of an all-purpose canoe-- the one most likely to be fitted for sailing or to have sponsons attached to its sides... and even though it's for "heavy water", it does okay on the lightweight stuff too.
You'll notice that the GS comes in 18 and 20 feet... while the HW comes in 16, 17 and 18. So, the GS is designed for holding a lot of people and stuff and a couple dogs too. Those who want a utility canoe that comes in smaller sizes and is more easily portaged may prefer the fifty pounder.
Notice also that the GS was available in three grades.
Others here may have thoughts to add, from personal experience. If you're curious about canoes of a specific year, any of us who have the catalog CD can look it up for you.
Kathy