First, welcome to the forums.
Second, nearly everyone has experienced cold sores; hence, nearly everyone has herpes II. So, here's the question. Would you asked for papers on someone you dated in the vanilla world before you'd kiss them? I'm guessing that you wouldn't.
Third, if someone were to show you a set of papers, what do you now know? Since there is no system-wide format, you'd have no idea that the report is legit.
Furthermore, even if it's legit, you'd have to know that the person in question has been quarantined since the collection date, not to mention the fact that that some things might not show up for months.
In the end, a health certificate proves little to you. Getting tested on a regular basis does much more for the person getting the test (in terms of awareness) than these tests could ever do for you, the prospective new partner.
Take a look through the Safe Sex thread here and you'll find that this horse has been beaten to death...many times.
There are many ways you can minimize your risks, but they will nonetheless always be there in this sort of activity.
Best wishes,
Tramp