Some conflicting info here so I suspect mismatched parts.
Last ditch rifles did not have the aircraft sights, they also often had wooden butt plates. The monopod was also missing. Another major concern is the bolt, the end cap appears to be welded, this is often the case with last ditch rifles and MAY be indicative of inferior steel.
Try to look at the bolt end cap of an earlier version 99, you will see the difference.
The welded end on the bolt end cap is a bad sign. But then again, the bolt may not match the rifle.
Yet the author initially identified it as a 38, well, no 38's were last ditch. They preceded the 99. Personally I think it's a 99.
As for chroming that has little to do with the steel being hard or not. Chroming is a surface treatment for steel. Many steels can be chromed, whether hard or not. Bumpers on cars are chromed and that is junk steel.
If you can confidently identify the rifle as built before 1942 you have a good chance that it is safe to shoot. But....NOT BEFORE YOU HAVE THE HEAD SPACE CHECKED.....!
If it is a last ditch it may not safely stand up to the pressures of today's ammo because of poor steel quality which would be difficult to determine without metallurgical help.
A good link on headspace:
http://www.surplusrifle.com/shooting...pace/index.asp