I have a few of these fixures (bathroom, bed, iirc) in my '61. The covering is very much like the white flourescent light covers--and I understand it's a satisfactory substitute. For the accuracy obsessed, the original light cover is made of translucent white plastic (I think the surface is formed in thin parallel ridges). You may have to search far to get an exact match, but I think the regular replacement flour. light covers you can get at Home Depot will do fine, even if the pattern is slightly different. I don't know how you could cut it, though--you may need to use a saw, since it's a little too brittle for snips and too thick and hard for a razor.