[78-L] LP or not LP, is that the question?

[S&R Pinsker]

A random spot check shows no non CBS family discs with the initials on the label.
Usual legends: Long Play, Long Playing, 33 1/3, and or microgroove.
Nothing on Angel; I suppose that by the time it was introduced, it was taken
for granted that 10" or 12" discs were LP unless otherwise stated (Conoisseur Society 12" 45's).
 rdp