i don't believe so. it looks like these might be the only options:
could be a good enhancement.
you can, however, create a token with
$job.runDuration$ and that will give you the number of seconds that the search took to complete, and possibly display that in the panel description?
if you used saved searches, you can use the _audit index to grab the run duration and create the token from that. the search is something like
index=_audit action=search savedsearch_name=* info=completed|stats sum(total_run_time) as runDuration by savedsearch_name _time
oh but sorry, yes, this would need to be inside of a dashboard, it wouldn't be visible in a report page.