When i was watching the pre-79s in the 1980s they always used the 1971 PBS Ident on episodes of Mr. Rogers from 1969 or 1970. Trolley Card thats at the end of the episode on the 1969 & 1970 episodes. Those were plaster over taking the place of the NET Ident. In the first run episodes when they were fresh, they were using the original NET Ident. I am thinking that even the early 1971 episodes may have originally used the 1970 PBS logo. By 1976 when the entire library was rerunning during those 3 and half yrs hiatus they all were using the 1971 PBS logo had trolley cards intact at the end.
1971 PBS logo was seen in the summer of 1989 on episodes of Mr. Rogers from 1066-1130, 1131-1140.
Starting in 1990 1141-1210 were using the 1989 PBS 3-D Glass logo. Instead of the classic 1971 logo!
Hope some of this helps!
lef
