I would never gainsay anything said by Michael Barone on politics, especially at the micro-level. I believe Gallup's LV model is highly tied to interview questions from which they determine likelihood.
In this cycle, it would also correspond to the Party-ID model: Rasmussen actually shows Party ID for Republicans is very close to where it was just after 9/11, which was huge. A FReeper who subscribes to Ras's pay-page claims that Ras is currently coming in under Gallup only because he isn't even using his own LV model, which would be R+1, and is sticking with a very conservative D+3.
Thanks, Fred.