This would be the likelihood, yeah. I've read a few theories that Barry and Ollie's powers are switched, or rather, Ollie would get Barry's speed, but that wouldn't remotely explain why Barry is suddenly a skilled archer, and why Ollie is a skilled speedster, so yeah, presumably within Elseworld (somewhere) we have Barry Allen as the Green Arrow, and Oliver Queen as the Flash. I was kinda' hoping we'd have the crossover with (our) Barry and Oliver, and Kara (etc) but this, seemingly, may not be the case. It's possible this entire crossover will be completely new characters, none of which we've ever even met before. I guess it depends on whether or not Gustin & Stephen are portraying more than one character for the crossover event.