Bottom left of your fender tag it says SQ which stands for Sequence, which I believe means month and day for scheduled assembly, based on when the order came in - and is not necessarily the actual date of assembly. There is some debate about that, but it stands to reason that it's the actual scheduled build date, which could result in the car being built a few days after that.
This my understanding as to how to read tags for assembly for 1966 cars. I don't know if it applies to 1960 or 1961, so I could be wrong.
If I read the code properly, it says July 1. A late build for whichever year we're discussing here. Assembly would have stopped soon after so they could prepare the assembly lines for the subsequent year's cars.
Since assembly of a particular model year started in the later months of the year prior, anything built October/November/December of the model year would have A B or C as the month. So if a 61 was scheduled for assembly on November 23rd, 1960 it would read B 23.
Again, I could be wrong.