The photos may not show the true deal but it looks to me like it has already been cleaned up a bit and what is left is pitting, especially that barrel end shot. It doesn't look bad as is and some further light cleaning should help it some.
If you want to look at one that had quite a bit of surface rust but little to no pitting, I have before and after cleaning shots of a rifle I picked up at an auction a couple of months ago here:
Type 99 auction rifle