I just saved a Zenith CCII from the trash.

[zeno]

The model number starts with a single S. This makes
it a big store set. Probably came from a major retailer
although we could sometimes get them as drop ins.
K-line is the switch over to 1st gen System 3. Top
line 25" & 2 19" sets came that way. In L-line almost
all were 2nd gen S3 sets ( 9-160 ) with a few uprights on the
lowest end sets.

73 Zeno