I tested every one of these old C-6 ribbed cone or flame tip Christmas light bulbs and they all light up fine. There are 31 bulbs marked USA, GE, W (I assume for Westinghouse) and Japan. Most are ribbed cone or flame shape, and most are American made. One is shaped like a bottle, one is a squarish clear bulb, and another is a different style of flame shape that resembles a flower bud. There are 3 extra bulbs that didn't light up for me (not shown). Several bulbs have missing paint to various degrees.

Also included is a Noma C-6 light string with 8 sockets. It works fine as shown in the second picture. Please be aware that some of the bulbs may have been around since the 1930s or even 1920s. While they all presently light up, I can't guarantee how long they'll last.