It could be, but my blind guess is that if there are any intelligent lifeforms out there, they're so far away that conventional propulsion craft would have to fan out and run for so long that it's unlikely they'd happen to run into us at all, or if they do, not at a time when any of us exist. And if they were already doing that within a reasonable distance from us, I think we'd probably have already seen evidence of some of the swarms somewhere.
And it'd also probably have to be immortal autonomous machines rather than anything biological, which wouldn't necessarily be as useful, unless they fully merged with them or created ones that were much smarter than they are. (Which I suppose is pretty possible, given we might do the same within a century or two.)
My guess is we may unfortunately possibly be the only intelligent life throughout all of reality up until now (extremely speculative, I know), or that the few civilizations that do exist or have existed are so spaced apart from each other that it's very unlikely any will ever run into or observe any of the others without some kind of major FTL breakthrough.