I think it's reasonable to assume he's accurate.
I don't think that if the Sky and Solstice have the same motor, they would be different horsepower and torque. At least not by a few horsepower.
And if the Solstice and Sky do have different motors, they wouldn't just have them different by a few horspower and lb-ft.
My guess:
The Setting: somewhere in a Saturn marketing meeting conference room
MarketingBonehead 1: "hey, we got this hot looking roadster, and the NAIAS is in six weeks, but so-and-so is late with the marketing literature. We gotta put whatever info is available together and get it to the printer TODAY!"
MarketingBonehead 2: "We could put some stuff out on the internet. What's this got that makes it go - I forget what it's called..."
MB1: "an engine?"
MB2: "Yeah, that's it! Now, unh, what type of... unh..."
MB1: "engine..."
MB2: "yeah, in-jen. What kind of "in-jen" does this car have? Man it looks hot!!!"
MB1: "I think it's called an Ecotec"
MB2: "let me look that up on the internet." Keys clattering. "GOT IT! Says here the Ecotec 2.4 l in the solstice on Solsticeforum is making 170 hp/162 ft-lb torque."
MB1 calls up the printer, with phone in hand: "Get the website updated, we've got about six weeks, that should just barely be enough time. Try and get the guy working on that OnStar find-the-message thing - I heard he's good!"
FIVE WEEKS LATER
MB1: "oh, man. I didn't know Pontiac was updating their information!!! Now we're 7 horsepower and 7 foot-pounds, whatever
THOSE are, behind the Solstice. I thought we were using the same engine?"
MB2: "We are using the same... unh... "in-jen". Maybe we should have talked to Pontiac?"
MB1: "What the heck do THEY know?"
MB2: "Well, all THEIR literature is reporting 177 horsepower and 169 foot pounds..."
MB1: "It's gonna take weeks to update everything... It's all SOLSTICEFORUM'S fault!!!!"