Merlot is one you may want to try. It is a deep red but should be tested on a hidded spot before use.
I tried to check the stock on my Type38 but the screws are untouched and I couldn't get the handguard off without tools so I am not willing to pull the stock off. All indications are that the stock is original to the rifle and has original finish.
As to the Japanese using different colors of stain. I think the shades varied a little but not much and then later on they switched to not using a stain or using a very light stain.
The Type I rifles are usually tan and have the standard Carcano finish. I suspect that Beretta finished the stocks out to their own specs not Jap specs.
I own firearms not to fight against my government, but to ensure I will not have to.