Per John L., if a 30-1/2" wide model (like this one) has the exposed coils up top, it's a HGD system. The later ones of this same size that don't have the coils up top use a resistance heater to defrost.
I finally copied and pasted his recent statements about this into a Word document that I can refer to when a potential candidate shows up.
This one is the right size and door swing for me, but coppertone is a non-starter, and since the fridge is too, I'm out.