Suburban heavy duty alternator still available?

[wizardberry]

I ordered a 2009 Chevy Suburban and received it about 3 months ago and got the trailering package and the 2LT options... I could have swore there was a heavy duty alternator option - but I can't find it in the order spec or the online build-your-own on chevy's website. What gives - do they not offer it as an option any more or is the heavy duty 140amp model standard on suburbans?

Thanks,
Michael
Suburban Parts (http://www.chevyclub.org/chevy-suburban-parts.html)