Coils are not internal combustion chamber or crankcase parts and as such I imagine the AM ones from China will be fine and you can possibly buy a dozen or more of them for the price of a single OEM unit...... if you can find an OEM new unit.
Coils, electrics, plastic covers, sprocket/clutch covers etc are all fine to use AM for- they have been making electronics over there for a good long while- generally they make some pretty good stuff in that line.
If an AM coil set gets the saw up and running,you can use the saw while you search for an OEM one.