I can't be 100% sure Allan but I think that it has no role. Looking through pics I took of an original low mile bike strip down, there was nothing connected to it. It's probably safe to block it given the earlier ones didn't even have it.
FCZach would've seen a lot more air filters than any of us bar Vader himself, any insights Zach ?
Sydney, Australia. The new leaner, trimmer shed: RE5M, RE5A, GSX1100EX, GL1800/Champion sidecar