Titan Tankless Water Heaters

Anyone able to help me determine the age of a Titan Tankless Water Heater? I have been unsuccessful finding this info online, and even after a call to the manufacturers service department, I was only able to determine that the unit is more than 10 years old, but they could not give me a year of manufacture.

(Sorry, can’t get picture to post)
Sticker is blue, says “ARL” “LISTED REINSPECTION SERVICE” “002935”

I’ve found many tankless water heaters have the same issues. The serial number data just isn’t published.

If you called the manufacture, and they can’t tell you, it would be reasonable to assume no one is going to know more than they do.