Nope. There isn't a line of sight since the combustion mixture is sprayed around the combustion chamber like a fire sprinkler rather than directly into the crown of the piston. Besides, you're talking about pinholes in the prechamber.

Here's a picture that shows the business end of a prechamber -



But who says you have to use a rigid rod? Use oil and a graduated cylinder to observe TDC.

Sixto
87 300D^2