They were on the brick pillars around the wrought iron fence all way around the perimeter of the front and 3rd and 1st base sides of stadium. I'd say mid 2000's or so. I believe they were still up when the renovation occurred.
There was a chain link fence around Olsen until about 2001 or 2002, then they put up a metal fence and brick columns with those globes on the brick columns, like the poster above me stated.
Now that I think about it, the iron fence may have been installed the same year the covered batting cages were installed... Or it might have been the year before. I've drank a lot since then.