I have seen some of these amber colored bulbs. Any colored flashbulb can be used with black and white film. For color film applications, blue colored bulbs were designed to give a daylight balance, or you could use a clear bulb and a #80C filter over the lens.

Kodachrome type A was for use with Photofloods. There was a color conversion filter for using Type A Kodachrome in daylight and this filter was a pinkish amber color. I think that it is a good guess that these amber bulbs were probably for use with tungsten balanced color film.