Also...just hopefully a helpful note here...
Write down the engine numbers and keep in a safe place
On Briggs & Strattons (on that generator) you should find 3 numbers on the valve cover. (If not on the valve cover it will be on the (usually) silver / nickel plate on one side or the other of the engine.) The numbers can be hard to actually read as they are stamped into the metal but the stamper must have run outta ooomph on a lot of them because they ar lightly stamped.
It will have a model number, trim and code and look like
12A123
281011
1991 E1
The top number here is the model number or 12A123 (or just Model 12 for short)
the middle number is the date of mfg November 28, 2011
the bottom is actually the code that tells where it was made and the trim (options) it has.
As of this reply I am not 100% sure of the actual order on the valve cover, but the model number is always easy to spot with 2 digits then a letter then 3 or 4 digits after that
I also know that the numbers should be on the box / crate, but I never trust some factory employee getting the stickers right on the correct box for the correct machine. I always physically double check them