schneider lens question

[dub365]

where is the serial number on a 75mm f5.6 multicoated super angulon? I many be purchased one from an a party who tells me they cannot find one. odd?

[Aender Brepsom]

It is on the outside of the front element, under the words "Lens Made in Germany". It might have been erased by the push-on lens cap, but I highly doubt that it could be completely gone. Sounds a bit weird to me.