User blog comment:NoodleBooty/My iLost My Mind Speculation/@comment-2246006-20110611225610/@comment-2032682-20110612031145

My idea on that:

iDSAF was filmed first, but only because Jim Parsons being the guest start for iLMM wasn't going to be available when shooting started.

People said the day he filmed his guest spot they worked till 2 in the morning. That's the type of thing that generally indicates a 'one day only' window.

So iLMM is the first episode, but it was shot second. iDSA&F is the second episode, but it was shot first.