Yes, that's the smart thing to do. I didn't know that when I had my tipover, but I let it set for several hours before I started it, and no harm done.
I did the same thing with my B2910 when I tipped it on its side about ten years ago. What I found out later is that the likely path for oil into a cylinder is the PCV route and not leakage past the rings, if the tractor is righted fairly quickly.
So trusting oil in a cylinder to leak back into the sump past the piston rings seems better not done.
In my case I figured (apparently wrongly) that since I righted my tractor in less than an hour there was no time for much if any oil to leak past the piston rings. I was lucky in the end...next time (I doubt there will be a next time) the glow plugs will come out just to be on the safe side.
