I suspect it is. all the tubes in it are labeled TEN/Rincan. 50C5 has a moderate H-K short but it still sounds real sweet.
Interior image: Really spacious in here, all the tubes are secured with small metal clips.
Update 2/9: Ended up replacing the 50C5 after it began randomly breaking into fits of "music-eating hum". It's now running on an RCA 50C5 with no more random blowing hum
