I'm no machinist either but I went ahead an ordered the set that Dirty Steve linked to above.
That set is manufactured to the class ZZ. A quick Duck Duck Go search turned up what that class means. I think that is close enough.
This is from https://www.meyergage.com/abcs-of-gages/differences-between-z-zz-classes-of-gages/
TOLERANCE OF GAGES
The differences between classes of gages like Class Z gage and Class ZZ gage is the deviation allowed in the manufacturing process for tolerance and geometry and does not define the useful life of the gage. Helpful reference materials are as follows, below is a sample from B89.1.5-1998 ANSI / ASME Standards:
Class ZZ has an allowed deviation of .0002″, geometry of .0001″, finish 10 micro-inch Ra
Class Z has an allowed deviation of .0001″, geometry of .00005″, finish 8 micro-inch Ra
Class X has an allowed deviation of .00004″, geometry of .00002″, finish 4 micro-inch Ra
Class XX has an allowed deviation of .00002″, geometry of .00001″, finish 2 micro-inch Ra