Yes, Jonathan Club is a private men's club, also referred to as a "luncheon club" in downtown Los Angeles.

Membership is / was executives from downtown businesses as I recall. Lots of bankers, etc. in the days when I worked downtown.
Had lunch there a few times in my banking & consulting days. A former boss was a member. White tablecloth service, good food, someone else picking up the tab! .

I think they had gym facilities there, but no golf course to make it a full country club-type facility. You know the look -- reading room, paneled walls, old-money feel. Any gambling was incidental to its overall operation, IMO ... but where's there's money & leisure time, a "friendly game of cards" would make sense.

Housed in a stately 3 or 4 story building, but during the high-rise building downtown, they sold their "air rights" for a fortune back 20-30 years ago.