Yes, one foot and one hand to steer one way, add the hand master clutch, and a 5 speed and direction change lever + the power control lever for the blade on my D7, you need to be an octopus! Funny though, a lot of the roads in the U.S. were built with these, not to mention WWII infrastructure, Alcan highway, etc. + all the dams and civil projects, its hard to imagine doing a 12 hour shift on one of these.
Just pull the dipstick, it should be obvious when you look at it, there is enough on the stick. When running the starting engine, cranking the diesel, oil pressure will come up, though I realize you can have pressure and not volume with some things, if that stick has enough showing it ought to be fine, you can sort the details of the tractor later, I thought it was interesting that early tractors are to be shut off to check and the later ones left running, always wondered why they went with it running, on my D7 if not careful that fan will blow dripping oil back on ya.