Sam, Not to be a smart a**, but the bulbs you are describing have a bayonet base, like taillight bulbs. The bases for those bulbs in the Hilo are unusual because the bulbs need to have two contacts with a single filament. Most automotive bulbs are not that type. They either have one contact and one filament or two contacts with two filaments. I don't remember what the proper bulb number is. I learned all about those bulbs when helping my dealer friend work on a Classic. One of the fixture bulbs was burned out so I went and got a single contact bulb and put it in and immediately blew a fuse. The bulb shorted across both contacts. I hope you find something for a reasonable price.
Added note: Look for a cheap taillight at Walmart or an auto parts store. Maybe you can tear it apart for the socket to rebuild the fixtures.