The parts may be new.
But what I found was the tube that ran from the gas solenoid to the main burner had some filings from when the flare fittings were machined. The little bit of oil and aluminum dust caused an in the field repair. Been working fine since.
Your water heater has a standing pilot, so your main orifice is practically part of the valve assembly. Removing and cleaning it may get weird?
TT 2015 19RD "TheJayco"
TV 2003 F-350 "Montblanc" - Housebroken chore truck
Sitting in The Cheap Seats.
And proud of it!