This area of partnership tax is complicated and I am sure that the preparer of the tax return is a Big 4 Firm that has done this a time or two (or is at least reviewing the return).
Having said that, individuals make mistakes.
However, you are not comparing apples and apples between the two K-1's. When the "built-in gain" box is checked on a K-1, this is determined based on FMV at the date of contribution (where FMV is greater than adjusted tax basis) which will not agree with the "old" K-1 books and records. Essentially the assets were booked up as a result of this event. The preparer of the tax return will handle any Section 704(c) implications from this book up event and will run those through the "new" K-1 on line 1 (or appropriate line).
I'm a little late but I am working on my return. I've read the other messages but I am still a little confused. If I indicate that this is a "Final K-1", it then asks for what type of transaction on the K-1 worksheet. I am thinking that this is not a taxable sale which is not an option. I could put the purchase and sale dates (although it doesn't seem to be a taxable sale), the proceeds and then use the proceeds as the basis in order not to trigger gain or loss.
Am I doing this right or is there another method?