Agree.
Of all the knowledge I lost and gained since obtaining my PPL, Met was probably the highest net gain. In other words: I learned a lot more about Met than was ever examined at the PPL exam, since doing the exam.
I also hold a gliders pilot license, maybe that's a factor as well. It is very useful to be able to look at the proper Met charts and predict how thermic it's going to be tomorrow...
So, yes, learn the symbols instead of just expecting that you can reference them later on.