I have a list of Zeiss numbers but when I checked they are only for post war. The Contax is a lovely thing, the ergonomics are a bit odd, but the build quality is sublime. The pre-war Contaxes are a bit prone to shutter problems, does yours work OK?
Also, the uncoated Sonnars are excellent performers, even by today's standards, and the lack of coating doesn't seem to affect these lenses as badly as some others. The contrast is still really good.