Hi John,
Depending on how many Functions you have changes and corresponding Risk IDs affected you can just generate rules for those risk Ids in production after transport from DEV.
But when you are transporting from DEV make sure to uncheck the checkbox "Include All Action Rules".
By this way your existing rules doesn't get changed and for the risk IDs to which you made changes you can generate the rules.
To enable the option to "Include All Action Rules" with GRAC_TRANSPORT_ACCESS_RULES program implement below SAP note:
2007158 - Generated Action Rules are not transported
Regards,
Madhu.