Numbers, numbers!?!

[ILENGINE]

Not always. Just they engrave the serial in the plastic on some models and then it get worn away.

Normally on the flat part of the housing between the muffler and the chain cover on the chainsaws.

 

[StarTech]

I thinking more of the brushcutters where the serial numbers are engraved on the clutch/flywheel covers so when you change one you must transfer to the new covers. Some the ones I work on these are barely readable due plastic deterioration.