First off, that is a beautiful gun and the SAT (sight adjustment tool) is very nice too. I think it's highly unlikely the box is original to the gun.

It seems somewhat uncommon for that vintage of gun to not have grips numbered to the gun so I think the grips are more likely than not to be from another gun but in the end there's no way to really know.

All we know for sure is:
1. The gun is beautiful.
2. The grips are beautiful.
3. The box is labeled for a k-38 Masterpiece.
4. Various numbers are written on the box, one which matches the serial number for the gun and one which matches the numbers for the grips.

Any other conclusions are speculation.

glowe gives a reasonable explanation.

The K301 scratched out looks like the same style as the K310405 below it. I would suspect the person was starting to write down the serial number and realized they accidently wrote K-three-zero-one, switching the zero and the one, and then scratched out the incorrect start to the serial number.

John
Scoundrel and Ne'er-Do-Well in Training