It just means that they swapped in another bolt to make the headspace come out right when they were building the rifle in Hungary. As long as it has a number its still a military bolt from a Hungarian service rifle. Same with the barrel - if you remove the gas tube so you can see the top of the barrel, it has many proof marks and a number which probably won't match the other numbers. This is mostly how they came.
Anyway that is a great rifle to have, and we will never see genuine European AK factory rifles that came in completely assembled with the mil barrel again.