No, it's the year that's different. Light argent sombrero = '70, Dark argent sombrero = '71, acorn with detachable centers = '72, acorn one piece after that.
As for values. AdamR has it right. Opinions are all over the board on this, so I won't even weigh in, other than to say obviously you can get whatever someone will pay you. However, on the SBP acorn centers, if some opinions in this thread were correct, then I guess I should have jumped on all the $100 sets of 4 I saw at every single swap meet I went to all last year. Apparently they were dramatically underpriced.