Frame up really doesn't matter. Frame down is critical. If you look at other threads, pontoons can be rebuilt. The turn tables can typically be repaired if needed. But the rollers are the most important thing to look at. There are (should be) 248 of them on a 442. A lucky few, myself included, only have 240 since the tracks are worn / 'stretched' and one grouser has been removed to shorten track. If the machine has 10-20 bad rollers, you may be able to track down replacements or pay to have some machined. More than that then you need to consider your wallet (or reduce the up front price). Originals are no longer produced and are protected like golden eggs for that reason. The average cost I've seen here of people trying to machine them is around $40. Each. So, you can see where that can add up quickly. But if they get their regular greasing on time, they won't be a problem.
What do you plan on using it for?