Already several years ago I had copied an image of the same stamp (Nr.7 1984), likely from ebay - where the weight was described as being produced by one of the Zimmermans.
If you search the net you'll also find:
There is a backstamp mark that reads CCMSA No.1 1978.
CCMSA Pear Shaped Art Glass Paperweight light green with bulbous effect in middle. 5 1/2" tall X 3" wide. In excellent condition no chips, cracks or scratches. marked CCMSA 1980 No.3 on bottom. Substantial piece weighs almost 2 lbs.
Blown Art Glass Paperweight White Floral Trumpets Signed CCMSA 6 (no year mentioned).
This looks like an annual event, first organised in 1978 - and there are quite a few organisations with CCMSA as acronym. Still doesn't tell us who made the weight(s).