This is a bit of a strange one. It's plastic, with a brushed finish. The Conn logo stamping has the four-pointed star and wreath that was used from 1964-69, but without the model number beneath it. The serial number is stamped high on the lower joint, and isn't a Conn serial. The keywork definitely isn't 1960s Conn - but it sure looks the same as that of the oldest Artley 18S I could find on eBay (which also has its serial number stamped high on the lower joint instead of at the bottom). It also has a very un-Conn-like .580" bore. The serial number would fall in 1972 for Artley.
So, for the most part, this makes sense - it's almost certainly a 1972 Artley with the old Conn logo stamped on it.
But... why? And what model? The October 1971 Conn price list has four soprano clarinets: The Artley 18S Prelude, Conn 17N Director, 38N Connstellation, and 78N Connquest. The 17N was a wood model in the '60s, so unless they immediately reused the model number, it isn't that. Conventional wisdom was always that there were no Conn clarinets after the Elkhart factory was closed, but the price list refutes that.
On the off chance someone out there has more information than what I could figure out, that'd be appreciated - but regardless, whatever this is, if they built one they probably made more, so I might as well post it here for the sake of those who might have one of the others and be connfused as to what it is.
(Also: too bad the H-ligature is cracked...)