If I remember correctly Stihl doesn't have a way through serial numbers to tell age of their products. The 015 was made I think from mid 70's to early 80's. The only way would be to either contact Stihl with your serial number or talk to a local Stihl dealer, but I think they will only be able to tell you what I have already told you. When Stihl manufactures their stuff the serial numbers are in order from the start year of their products, and should be able to tell you what year in relation to where your serial number lands in their years of production for that particular model. (I believe this is correct, if I am wrong don't tell my wife....one more thing she can say I am wrong about.):laughing: