Check Numrich, you can get repro stocks from time to time. Ebay or gunbroker have original stocks but often for more than the rifle is worth.
I have just about every part you could want for a Japanese rifle. But, you need to find a stock first.
Post pics of the rifles and pics of the top of the receiver and the marks next to the serial numbers and we can atleast give you an idea of whether or not you should even try to restore them.
I own firearms not to fight against my government, but to ensure I will not have to.