Yeah. Heck, does FO3 even keep track of most of your ingame decisions? I don't think it does. Mass Effect was designed to from day one, but I'm pretty sure that FO3 doesn't.
I'm pretty sure that considering some dialogue with your father, it does.
After all, it's as simple (as far as my limited coding skills are concerned, so feel free to correct me if I'm wrong) as checking a couple of variables (there weren't many important decisions in Fallout 3 after all, though there were a lot of little ones in side quests and such).
So if they wanted to, they could, though again, games aren't connected storywise.