Hi Lee,
In Production system, client setting is correct (no changes allowed and no changes to repository and cross client customizing objects)
PFCG, Default transport request should be display in production system because of any modification in local object so we can used it.
Production level for system is 1 because its no overwriting but external availability is there.
or otherwise if you don't want transport role option in PFCG, you can disable a particular icon using t-code SHD0 (screen varient)
Regards,
Dhuvaraganathan M.