Hi, Paso Bob.
I didn't have a lot to do with them but I didn't see a lot of them broken down either. They seemed to me to be a pretty sold tractor. They did seem to be better balanced than the earlier F series which were a little light on the front with the first of the 6-bangers in them.
Just my 0.02.
Love the D7G! easy to maintain, built heavy, 7/8" roller bolts instead of 3/4". 3306 is a great motor. Find out if you can, records. With that many hours the turbo may need a new cartridge. If you can check magnetic filters, oil colors/levels, cut filters open/check between pleats, check for growling noises/trans/final drives, pump whining or howling, chattering noise in hyd tank, ticking noise from exhaust manifold leaks. And of coarse basic undercarriage wear. I really like the combined steering and braking.