The BR 500 is the turtle back unit or the 4mix unit. Stihl hit the market with the 4 mix stuff around 2001/2002 the first 4 mix to hit the market was the FS 110 Grass trimmer, the 4 mix blowers came later, I believe 2003/2004 so it can't be any older than that.
I just looked up your serial number and it shows that your blower was never registered to the stihl system. IDK who you bought if from but they messed up.
