Correct.
The part number for the tensioner is 89440 and it'a a Dayco.
The tensioner came with a flat pulley for a 12 rib which was *HUGE* and ridiculously heavy.
I swapped it for a 10 rib double-bearing idler from a Volvo truck that I got off ebay for cheap.
But it seems that any of the 10 rib double bearing truck idlers are the made to the same spec/dimensions.
Which makes sense for heavy duty commercial vehicles that require a lot of maintenance, common parts for many vehicles.
I have an aluminium version of the double bearing idler on my shelf full of parts, i think from memory i got it from american racing solutions.
Any supercharger belt tensioner should theoretically have better action with a lighter idler pulley.
Here's a cool video of a drag car showing the abuse a tensioner has to endure during staging on a two-step, and how much a belt stretches under the horsepower.
Real eye opener!