It should be just fine, even if the AeroShell Grease-33 canister were stale-dated.
After all, the wear & tear on the AP mount’s worm gear isn’t nearly the same as on a jetliner’s massive landing gear retraction and wing flaps mechanisms, for which the grease is normally used.
Let us know if the date on the Amazon-sold tube that finally arrives, actually is out-dated. Wouldn’t want others to go through the hassles of AP mount gearbox removal etc. for lubrication with less than a perfectly stable grease.
I recently learned a similar “Amazon Quality” lesson, when I bought a large box of hard to find, Full face (small centre hole) AVERY DVD labels. Turned out that the box of labels was VERY old unused stock, from some music company’s shelf, and the labels backing adhesive was out-dated – according to AVERY specs. They didn’t stick well to the media, messed up the Laser printer rollers.
I think there could be a lot of unscrupulous dealers out there, peddling left over junk, and hiding under the guise of Amazon’s presumably good reputation.
Caveat Emptor, as they say.
At the risk of muddying the waters, I also wonder, if the “AP Special Mount Grease” formulation is even permitted to be shipped overseas in air-cargo, given that it is potentially a fire hazard, possibly explosive canister in the high altitude unpressurized airplane cargo hold. Might be limited to only local “CONUS - courier truck-shipments”. That may be why the original poster can’t get this AP product in Italy, unless the unique AP formulation is mixed right there, on the AP dealer’s store premises, using locally obtainable “lube component” supplies.
Hopefully, there is a solution. Otherwise, AeroShell Grease-33 is certainly an AP-recommended, excellent alternative, and a lot easier to source and buy world-wide from a local ... airport supplies service center.