ok, here's the scoop in short, a complete PDF can be found on the SCCA SFR Region Website:
==================================
Driver License: A current racing license issued by SCCA, SCCA Vintage, or any of the following will be
accepted with proof of current SCCA membership:
• Classic Sports Racing Group (CSRG)
• BMW Car Club of America (BMWCCA)
• Corinthian Vintage Auto Racing (CVAR)
• Historic Motor Sports Association (HMSA)
• Historic Sportscar Racing Group (HSR)
• Porsche Club of America (PCA)
• Rocky Mountain Vintage Racing (RMVR)
• Society of Vintage Racing Enthusiasts (SOVERN)
• Sportscar Vintage Racing Association (SVRA)
• Vintage Auto Racing Association (VARA)
• Vintage Auto Racing Association of Canada (VARAC)
• Vintage Racing/British Columbia (VRC of BC)
• Vintage Sports Car Club of America (VSCCA)
• Vintage Sportscar Driver’s Association (VSCDA)
• Vintage Sportscar Racing Inc. (VSCR)
• Vintage Motorsports Council National License
==================================
here's the link to the event site:
http://www.sfrscca.org/RoadRacing/Vintage/it seems you have to be a SCCA member for the event, but other club licenses are accepted.
all rules and requirements can be found on above event site (there's a PDF you can download) ...
Andy
PS: altough POC and PRC are not on that list, i would be surprised if they didn't allow those as well ...