I'm looking at buying it in the sale hoping it does. I already own SR2 on it but the price of the DLC still is ridiculous.
The PC version of Saints Row 2
never had any of the DLC ported, apparently -- probably due to the godawful quality of the Windows port. The DLC were only available on the XBox 360 & PS3 (though some of the content included in the Gentlemen of the Row modpack for the PC version apparently is based on some of the DLC content).