Stihl HS 45 Hedge cutter Ignition Module

Hi 
I have a Stihl HS 45 hedge cutter which I bought at an auction, and need to determine its age as a correct replacement part is dependant on the age of the hedgecutter.
 
The only sticker on the machine says Serial Number 1 54190650  and 0000 967 3740A S
 
The part I am trying to replace is the Ignition Coil. The faulty unit has the following reference codes. SEM Sweden Type 42 809 205 26 4140 1302A 
 
From the info I have sent could you tell me the age of my machine and/or the correct part number for a replacement coil.
 
Regards 
 
Les Wilcock