I would hope that if you're developing a brand new rocket engine design to carry people, you'd welcome offers of peer review and do everything else you can reasonably do to help make it safe (like avoiding PR driven deadline pressure).
In the history of manned space flight, lots of unmanned experience was made before crossing that threshold.
As part of the CCtCaP (or whatever the acronym is) program, SpaceX and Boeing is giving NASA access to all the details for review. This seems obvious, since they are the customer. But to think that SpaceX and Boeing would reveal their individual trade secrets to each other seems unrealistic.
