looks like you are trying very hard to keep the traffic going on
As you can still *read* the Gileraclub Forum you may search for things like this.
Dimensions are 40x52x10(10,5)mm
The seals are also used in some Ducatis with a Marzocchi fork. Ducati 600 Monster and SS, 750S from 1988 to 1990 and 900SS from 1989 to 1990, with 40mm fork.
If you just have the fork legs in your hand it's worth to replace also the outer dust rings. You can just use the rings from the mentioned Ducs.
They have a longer lip and a spring on the outside. Since i have that type of dust ring on my Nordie fork i never had a leaking leg again.
BTW the fork seals also fit the GFR fork.
ciao Joachim