Believe they all came with 16.5 wheels and think the highest gear ratio was 456. And down to like 583s? Haha thinking you'd be floating the valves on the highway
As far as I know all parts are still available for those to keep it running for hair cuts and chick picking. LMC truck and brothers if you are looking for a new seat. Mine came with a back seat out of a van I think as they are kind of narrow.
I would recommend you say away from LMC - they just relabel products and slap $20 on the price - sometimes they don't even relabel the box.
Late 50's would be quite uncommon (not even possible) to see 16.5" wheels. Most common would be 15" (yes, even on 3/4 tons) or 16" ring locks with 17.5's and 19.5's as a less common option.