Handling Invalid hrefnum for Capture History

OK, now even more surprises with CaptureHistory as started here.

In my application, when my experiment is closed and then reopened, a particular state remembers that it should be capturing history, but the hrefnum is invalid. How can I prevent a call to CaptureHistory(hrefnum,1) from putting up a dialog about an invalid hrefnum? Can this be done within a try-catch-endtry block? My other alternative appears to be a hook before closing or at startup of the experiment to set my global to shut off the history capture.

Essentially, I would be wanting the equivalent of a /Z flag on CaptureHistory(...) as is so handy on operations to catch an error flag and handle it internally.