Off the top of my "head" the stock in front of the rear sight should
cover the top of the barrel up to the metal cap on the front to the
front sight. The mum shows this to be a surrender weapon. Missing
parts on rear sight my have been done earlier but if you want just a
shooter no problem. The shape of the bolt handle was the same on
both type 38 and 99. The length ? depends when it was made as
the Japaqnese didn't maintain the same length during production runs.
I've seen both long & short rifles. Ammo, Norma is your best bet.
Ballistics of the 7.7x58 is compareable to the British .303. These
rounds ARE NOT ENTERCHANGABLE !!!!!!!

If the cost of ammo
gets to much some people do rechamber to ??? Check with a
good gunsmith as to the condition, shootable or not.
It might be possible to rechamber to 7.62x 63 (30-06) or 7.62x51 (.308).
As a suggestion if you do rechamber take a fully loaded round of
your choice and see if it fits the magazine well.