Arisaka prices on average?

[Arisaka99]

There is no such thing as "lightly sporterized". It is either original or buggered. The rifle you describe in your original post is worth about $75-$100. I would not take any more helpful advice from your local "expert". While there were some variations such as Naval Specials that were hand fitted, the bolts on most Japanese rifles will work on others. However, they will need headspaced to be safely fired.