You could snag it up, and use it while continuing the search, and then resell it when you find something closer to what you're looking for, but I wouldnt officially settle on this one for a few reasons.
Manual defrost is a serious pain in the butt.
If it already has 30 years behind it, I doubt it has much longer.
That thing will cost a fortune to keep running! Energy Star is the way to go!
To be honest, we have one exactly like that one. It works great, even if its ancient. I have yet to see a difference in my energy bill from it and its been plugged in for 2+ years now. It also has the manual defrost feature and we have yet to defrost the bugger in 2+ years. I do wish ours had a lock like this one does though! We have come home to ballooned dogs from getting it open and helping themselves LOL
I personally would grab it if I were you. Its a great deal and it will/can store a LOT of meat!!!
ETA: I think because we keep it FULL all the time, it doesn't need to be defrosted. Freezers get overloaded with frost if they are not running properly or if they are not being used for their intended purpose...to store frozen goods. Just keep it full most of the time and you shouldn't have an issue with it.
If you do get it...either plug it in or have them plug it in before you get there, and let it run for a good half hour before buying it to make sure it gets cold fast.