No, most of it (about 3/4) came this year. Not that it matters really, the 2008 numbers matter just as much as his very solid 2009 ones do, unless you want to toss them out as September outliers. Of course doing that submarines any argument for Stubbs so I doubt that's the route you want to go. Also, a .360 BABIP isn't that unordinary from a player with a 21.8% LD%.
If you want to compare what Stubbs and Dickerson are likely to do going forward I'd look at what they've done over the previous two seasons:
Dickerson:
MLB (421 PAs): .283/.383/.440 - .823 OPS
AAA (414 PAs): .287/.384/.479 - .862 OPS
Stubbs
MLB (196 PAs): .267/.323/.439 - .762 OPS
AAA (556 PAs): .272/.353/.379 - .731 OPS
Let me put it this way, if there were some way to wager on the respective lines that Stubbs and Dickerson put up vs RHP in 2010, I would jump on it in a heartbeat. I can't toss out Dickerson's last 850 PAs as fluky while accepting 200 PAs from Stubbs as indicative of his true skill.