Sure, with Honda's 'continuous improvement' process, it can be easy to lose track of parts supersessions.
It needs to be remembered that Honda's technology in the field of pistons and their sealing is world-leading; especially their Formula One race car, and Grand Prix racing motorcycle, engines - e.g. the NR500 racebike used oval pistons!
And this does trickle down to their more mundane products, such as OPE engines. So advanced design features, which other OPE engine makers don't use, can occur.
