Yes ... assuming that they are actually having "a kid" adjust it.
But looking at a staff photo of the shop it doesn't seem likely.
FWIW, I've had a look at several YouTubes that show the back of the machine and it seems like the valve covers should be easy to get to. The valve covers are each held on by 4 Torx bolts ... can't imagine that it could be a problem.
Other than maybe getting a torque wrench down in there to tighten things once the adjustment is complete.
I looked over the procedure for adjusting the valves in the Kohler Service Manual. Seems pretty straightforward, outside of ensuring you're at TDC on No. 1 before you start:
Did do some checking and found out that the Hydro Gear service kit for the hydros is $94.57 on Amazon:
While that's kinda pricey for 2 filters and 5 quarts of oil and some assorted tubing and fittings the total of $277 - $100 for pick up and drop off = $177 for parts and labor on the hydros doesn't seem unreasonable to me ... though I'm guessing that I will probably doing it myself next time as it looks pretty easy ...