That must have been a heck of a garage find, I think Russia would also want to bid on that.
It’s not a stockpile, but several manufacturers outside Europe that could fill the gap, and allow the EU to fulfill its promise of 1M shells by March. I’m guessing Turkey, Pakistan, maybe Egypt. I think it was France who demanded 100% of the shells came from EU. Having failed, Czechia is pushing to bend that policy.