That's a Clark County, Washington plate, from about '63, I believe. Doesn't look like the photo was taken in Clark County though, judging from the dry-climate background.
"If those asshole husbands of ours bring back ONE more bird for us to pluck, I'll be plucking something off of THEM!"
That’s Dick Scritchfield on the left but I can’t ID the other guys. The car is the Sam Conrad roadster and it ran a Hugh Tucker built Olds, could one guy be Tucker?