coyote

Hi new here today...any old d21 gurus here?
My Dad has a couple D21, one with a cab and one without. The one with a cab has factory duals,or so he thinks...anyway I noticed a few want ads for these tractors. What are some features or thing to look for as to decide thier age or value. Both run and are strait, parked indoors for years.
thx coyote

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no answers...just questions here