I have a question about this EK1.

‘11′ Maker Marked EK1 is a perfect match with Deumer.

Q1: Is this a mistake on the maker’s mark? -> If so, did Deumer use the same ‘11′ markings as Grossmann??
Q2: Is this a post-war product? -> Like L15 marking in F. Orth

*Maker marking*

3 - Deumer PKZ
11- Grossmann PKZ
11- Deumer PKZ(??)

L/11 - Deumer LDO

Best regards,
S.W.