New build tranny changes?

[TKG26]

I started my build yesterday and noticed that there must have been a running change on the layshaft with it’s gear. The instructions show grooves to accept orings to hold the pins in place. Inside my bag of parts for that come a pre assembled layshaft with what looks like roll pins already installed. But the plastic no longer has grooves for an oring nor did any come in the bag..

Is this running change fairly bullet proof? I dont feel adding onrings to this gear would be wise without the grooves to hold them..

Picture of the original part:

The new one looks identical without the grooves.