Those old plugs look good.
I grew up checking spark plugs in snowmobiles but with 4-strokes and modern injected 2-strokes, those days are gone. Nothing like getting a jolt off the plug while checking for fire. Lucky, I stihl have my modded chainsaw. Even then a pulse tach is needed.
Here's some Kevin Cameron of Cycleworld Magazine.
https://www.cycleworld.com/how-do-yo...cle-spark-plug