What needs attention
An older register and newer duct repair coexist. The age of a visible cover does not establish the condition of the repaired system section. Which components were actually inspected and what evidence supports the current proposal?

Visible age does not describe the repaired duct section
An older register beside newer mechanical work needs records identifying which component was repaired and what was inspected. The cover’s appearance cannot establish the condition behind it. Ask where any claimed growth is actually observed and which parts of the prior work remain relevant to the present moisture question.
Let current component findings define the scope
The proposal should distinguish assessed material from sections inferred from their age or nearby cover. Cleaning and replacement decisions depend on that material and condition, with source correction separately understood. A newer repair should not be assumed sound everywhere, and an older grille should not justify an unrestricted duct-cleaning boundary.
Access for the affected space
If rooms were altered at different times, identify the relevant changes and retained materials. A room-by-room description is more useful than a general statement about the property’s age. For the cooling system, identify the actual unit and the person responsible for mechanical access and repair.
Related cleanup information
Coquina Sands service area; HVAC mold cleanup; Compare the cleanup scope.
Sources and further reading
Your next step
Talk through your mold concern.
Have the address, affected room and any known water history ready.