"This may be a stupid question but can the bolt be updated to a k31?"
The K31 employed a radically different design that dramatically shortened the entire bolt assembly.
Even if it could, there would still be the issue that it's chambered for an older, much less powerful cartridge.
When the modern 7.5 Swiss was adopted, several previous models were updated to take the new cartridge, part of which included fitting a newer, stronger barrel.
This was not possible on the 1889, so those rifles were removed from service.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.