I'm pretty sure the Community Edition Google Home Integration (CEGH) does support both locks and doors, including PINS.
So I don't think this is a limitation on the Google side of things, rather more of issues around what the native HE integration app exposes and supports in terms of capabilities. The CEGH version is definitely a bit harder to install, and the updates this thread mentions to the native integration (fans, etc) closes the gap, but I believe the CEGH application will do what your asking (and also exposes the source for you to make even additional changes if needed/desired)
