Having done some more investigating and rereading a conservation document I'd found previously, my salt may not fall into this category (but still undecided) however I'm going to have to disagree about the Medallion glasses.
The Corning very specifically includes single walled glasses with a medallion here in their document regarding the conservation of Zwischengold glasses (see page 15).
http://www.cmog.org/sites/default/files/collections/85/8595D55B-378A-4400-91C2-B7D20E08F616.pdfThey also start this document with the following wording:
'T HE T E R M Zwischengoldglas refers to several
different types of eighteenth-century
glasses made in Austria and Bohemia.
Meaning literally "glass with gold between," it is
an apt description of both the way in which the
glasses were made and of the nature of their ornamentation.
These objects are characterized by
having been assembled from separate glass parts,
which were cemented together, and by metallic
gold and/or silver decorations sandwiched in between
the glass parts. '
I do feel my salt can be included in this.
m