@Mike Rocket While it might be interesting to have that information, it will not be useful. There are too few Rockets overall, and the challenges among them smaller still, that a single data point (your questions) simply cannot be statistically significant.
Without taking an engine apart just to look, all of us are accepting some level of risk in operating a reciprocating engine.
So most of us focus on the grin, and if something happens, well, cross that bridge if/when encountered.