They are WGD carbs. Fuel inlet comes from the side of the bowl instead of the center. The 3358s is a 2400 series carb. Supposed to be original from the Buick line in the mid fifties. Turn the carbs over and measure the throttle bores. If the middle one is slightly larger, it is a good indication that this is a matched set. The larger bore middle one is rated at 280 cfm and the two smaller ones are at 250 cfm.