The Type 38 has two gas escape holes.
Those Type 99 rifles were not really the "last ditch"*; in spite of the shortcuts and crudity, they were still made of steel forgings and are accurate and serviceable. Yes, the floorplates, sights, bolts, front band and other areas were different from the early war Type 99. The most noticeable areas of change are the bolt handle, which was made a plain cylinder instead of the "plum" shape of the earlier Type 99 and Type 38 rifles; the floor plate and latch; the single aperture sight instead of the adjustable sight; the safety - missing on that gun; and the stock, which was roughly finished.
* The term is more correctly given to very crude rifles chambered for the 8mm pistol cartridge. Thousands were to be issued to civilians to help fight off the expected invasion. Had it not been for the atomic bomb, I am sure tens of thousands of Japanese and Americans would have died in that fighting and it could have lasted years.