Hi Neal,
This change was made in 16.0 SP02 under CR 746759, "New feature request to print trailer information from a dump archive. The new option is LOAD DATABASE <dbname> WITH LISTONLY=TRAILER." Engineering took the opportunity to pretty up the headeronly output. There isn't any option to revert to the previous format of the output.
I'm sure there has been discussion about storing dump history in a table, but the implementation that has been done uses an external file instead. Documentation is at Dump History File
Cheers,
-bret