Help ID my friends new a833

My Buddy just picked up this unit hooked to a 440, can anyone help identify what it came out of please? I ran the 10000 day calendar and found the build date is march 3, 69, has a ball detent style side cover. Thanks in advance. The 440 by the way is a 72, so we are aware they are not a matched pair.IMG_0974.jpg IMG_0973.jpg