The link is a history of them. Go to google and just type in Gilson and go to the images area and look at them. Some of them were real work horse. I'd bet it'd be in aclass very similar to some of my Bolens GT's, maybe not my HT23, but I bet similar in size and power as my 1972 1556 which isn't a runner, but it is to be my first attempt at a total take apart restore.
They're good light duty GT's; nothing amazing. By light duty, I mean they'll push snow and pull a heavy garden cart willingly... But the vertical Briggs aren't torque monsters, and attachment availability isn't all it's cracked up to be. The two Gilsons are worth what he's asking... But they aren't especially desired if you intend on flipping.
And if I had my choice between Fords made by Gilson or Jacobsen: It'd be Jacobsen all day long.