It's likely an exaggeration, but if so it's not much of one, and I can't rule it out actually being true at some point.

https://revealnews.org/article/want-to-carry-a-concealed-gun... is an article saying there were 2 in SF in 2014, and that they basically never issue them. (They apparently last for two years before being renewed). It was apparently still the case in 2019, according to the hover-map on https://www.fresnobee.com/news/local/article232198382.html .

I have been unable to find many other county-level statistics, short of making an FOIA request.

Feinstein claims that she no longer has a CCW permit, but that she once did. So while Feinstein once probably had most or all of the CCW permits issued in SF county, that is no longer true.