Interestingly, they DO fit a little different. Part of it, in my case, is the fact that I've had the Captains for over a year, so they're more broken in than the Scouts. The lacing on the Captains cover more of the shoe: it obviously extends higher on the ankle, but it also starts closer to the toe than the lacing on the Scout. So the Captain feels more secure; my foot seems to slip more in the Scout. Also, the suede on the Scout is surprisingly stiff; this isn't a pair of floppy desert boots. It feels like it took more time to get the Scouts to feel "broken in" compared to the Captains.
Both are good solid boots, though and I'm very happy with both.