I assume you know how to read 96099. The first 9 refers to it being a paperweight, the 60 refers to year designed ie. 1960, and the 99 is a design number for that year. Of course Lindstrand = Vicke Lindstrand its designer.
During the 60s and early 70s there seems to have been a fascination in Swedish design with bubbles in general. The fine bubbles are due to bicarbonate being added to glass directly, whereas the larger ones seem to be created by simply sticking sharp pointed objects into the paperweight and by a small amount of gas being trapped near the point, similar to the "controlled bubble" moulds. The Warffs for instance made many different "Bubble Sculptures" at Kosta more or less at the same time.
Lindstrand also made ones similar to yours, but using green glass to highlight the bubbles - see photos of an LH1828 paperweight of mine.
Ross