Mike: that is a good tip, never thought of the felt in 35 mm cassettes...hmmm...anyway the seal seems good enough, I will let it alone for the time being.
Just for the record, the film is Fuji Superia 100, expiration date September 2001. After seeing the negatives I run back to my friendly store and bought the 4 rolls they had left (at a good discount)

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The lab guy was so elated to see that corner of the film counter free after so many years that he gave me as a present a roll of Konica VX 400 with expiration date December 2000 "to try"...I guess he is a good saleman! The roll will be good enough to test cameras, and he also has a few more left...hmmm do I see a pattern here?
Thanks for the kind comments!