Caterpillar recommends the initial valve adjustment around 30,000 miles.
If a Caterpillar dealer did it, it should be recorded with Caterpillar Corp.
Call the Caterpillar RV engine hotline with your engine serial number: 877 777=3126.
Your engine serial number will be on the valve cover-- see it by raising bed or removing access door in closet.
Also, be sure to ask if you have the greasable zirk on the fan hub. Engines built before 1/03 have them and it is an often neglected service item. It can only be greased from ABOVE.