I'm not a "Arisaka expert" by any measure, but I owned 5 Type 99s at one time - used to buy them at gun showa years ago because they were cheap - I think the most I ever paid was $40. There were differences in them all - some had monopods, some aircraft sights, etc. One was a "last ditch" - wood buttplate, crude fixed rear sight, rough, not smooth machining on the barrel, bolt handle, etc. But, the bore was nice and the bolt locked up like a vault. I never shot any of them as I wasn't in to reloading then, but I am sure that it would have been safe to fire. Buttstock had some scorching on it that would lead a person to believe that it may have been near a flame thrower.
One issue on Arisaka rifled that I have heard of often is that the chambers can be on the generous side and/or not always concentric (i.e. a bit egg shaped) not always but something to be aware of regardless of the arsenal.
Right now, I am working with two Type 38 Arisaka rifles - of course chambered in 6.5 X 50, not 7.7 like the 99s. Both of the rifles are first year production - 1905 at the Tokyo Arsenal. One has the serial number 6X and the other 2XX. My uncle was a Navy Surgeon - his ship was anchored in Tokyo Bay during the surrender. Afterwards, when he was allowed to go ashore, he pulled them out of a large pile of surrenders rifles as well as 3 bayonets that I have. The rifles are in extremely nice shape, excellent bores and very well made.
I have read in a number of places that after the war, the govt. and the NRA tested the various bolt action rifles used in the war, and that the Arisakas had the strongest action of any of them. Working on and with these two Type 38s has given me a whole new outlook and respect for the Arisaka rifles - and that's saying a lot for me and my age as I am of the generation whose fathers were fighting the Japanese armed with them just a few years before we were born. I sold the 99s a number of years ago, but after working with the two 38s, I have developed an interest in them and if I run across another good one, in original state or sporterized, it will come home with me.