I was following this discussion a bit in another thread , and I read the bit about it only being by Erwin if the E is before the Eisch.
I have two "Peacock" pieces, with no marks, but one still has a beige (it may have been white once, hard to tell) paper label attached with a red cord to the handle.
It reads, unfortunately in ancient German script.
There's a d)" mark I have worked out is ch
and some f's are s's I just don't know which ones.
Mit deifem Glas erwerben Sie eine Befonderbeit aus dem Bayerifden Wald, eine Roftbarleit fur den Renner echter Glasmacherlunft. Entwurf u. Technil
flammenvon
unferem Runftler
Erwin Eifch
on the back there's a logo of black and white triangles in a block and
GLASHUTTE VALENTIN EISCH KG
FRAUENAU
BAYERISCHER WALD
I have always assumed these are not by Erwin himself.
More recently I got another piece, with is marked Eisch and dated '90. No E.
Looking at that, (I love it) it is really quite wonky and has manufacturing flaws I would not expect to find in the work of somebody who has a lot of experience, as Erwin would have had by '90.
So I'm quite happy to think if the E is not there, it's factory piece rather than one by the man himself. What I have supports that notion.