I believe the story you heard is correct. I received some of this material directly from the ex-Winchester employee who told me that Winchester was throwing the USCCo case draw collection boxes away and he liberated many of the boxes from the trash! In his digging he found some 9mm Glisenti ,material. He mentioned that this material was in boxes but what he he gave me was in a brown paper envelop marked “Maxim DS”. I suspect he didn’t want to waste neat old .22 boxes on me.
In my case he provided me about 35 pieces for the Maxim headstamped 9mm Glisenti made for Italy in WWI. The Maxim made cases had headstamp of medium size letters and dated 1917. In late 1917 problems at Maxim resulted in USCCo taking over the contract, and all Western production I have seen, except as noted below, was dated 1918 with small size letters, except for the cases in this batch which were dated 1917 with small letters. About half of these items (both bullet and case stages) had a small clip soldered on the back to be attached on a board. These appear to constitute a complete draw set. The others were just assorted draw pieces with one exception. One primed case, 23.26mm long, and dated 1918 with a copper primer has a poorly made shoulder at about 19mm. It looks like it may have intended as an extended case blank, but this is only a guess. The 1918 cases have brass primers, but a number of the 1917 cases in this group have brass primers, and have not been trimmed to 19mm, which seems strange to me!
Subsequently I found a single loaded round dated 1917 with the (USCCO) small letters and a copper primer. It is polished, which may have happened later, There is no indication it is a dummy, but it could have been some sort of inert display item. I have never been tempted to pull the bullet to see in it is inert.
If anyone can shed some light on any of the obvious questions raised by this group, I would be delighted!