Hi Edward,
That should be fine (all bundled RC curb styles are stored in _RC_Street_road_01.max & curb1.max).
I would suggest you to check material IDs of your "Base Object" - some curb styles use Spine's Material IDs to assign different types of kerb (ID 1 normal kerb, ID 2 drop kerb). In case your spline has different Material ID set, no geometry will be generated. Setting these part(s) of the spline to Material ID 1 or 2 where needed should fix.
Best regards,