Based on that story (and Chris, if you read something more detailed I'm happy to be corrected, but if you read something more detailed I don't see why they wouldn't co-opt it for more content on the site than just a picture), I'm gonna go ahead and suggest that "at the request of Drew Carey himself" is firmly in hyperbole territory.
After a firm application of Occam's Razor, here's my theory, and it has nothing to do with Carey sitting at home watching YouTube clips of foreign versions of his game show:
Larry's over here doing Morning Show stuff ('cuz if you're gonna come all the way to America you might as well bang out a few stories while you're here), and one of the stuffs is a walk-on thing for TPiR, because it's great morning show fodder and Mike Richards has never met a stunt he didn't like and therefore would be totally down with it. (And I feel safe in suggesting that Larry Emdur has a connection at Fremantle who can at least get Mikey to accept a phone call.)
Everything you read in that article was complete on-air theater. Larry walks out, Drew says "Hey, everybody, it's Larry Emdur from Australia who used to host this show down there!" Crowd applauds politely because a) the sign flashes and b) they have no idea who Larry Emdur is because nobody in this country knows who the hell has hosted this show outside of Barker and Carey. After some witty banter, Drew says "Hey, I have a great idea, why don't you help me host the next game?" Larry feigns complete shock even though all of this was planned out in great detail days before.
Really, folks, don't make this stuff more complicated than it is. From our side it's nothing more than Let's Do A Walk-On With A Foreign Guy Who Hosted This Show Where They Come From, and it doesn't matter if it's Larry Emdur, Marco-Antonio Regil, or Bruce Forsyth, because nobody in the US audience (outside of us geeks, pimple/ass/etc.) is going to recognize them. (Though in the latter case, it would be nice to see him, and to see him, nice.)