It the cutaways on the first site it's not showing any oxygen system and being it was a ground attack aircraft it may have been that they did not see a need for it but I'm only speculating here.
It very well may have. Like I said, I know very little about this craft and this is what I was able to find in a short amount of time. I'll continue searching cause you have me curious now.
Check this out. It is a manual for from Curtiss.You'll have to scroll down through it but it has two tanks for oxygen. Very interesting manual. you can actually download it to. http://www.scribd.com/doc/69325114
I saw that last night it was cool, I've looked at my Squadron/Signal Book and I can't find anything. Thanks T-Bolt, those look. I was just looking a the LeLv 32translated site and on the right side, There was an O2 bottle!