Lew - I have only one piece of material from Sampson Machine Works. It does not indicate Sampson providing anything other than the bullets, aluminum 38 cases and a decapping/priming tool. However, their literature points out that the 38 caliber bullets (they also made .45 and .30 caliber bullets, it seems from their literature) could be used in 9mm. they also provide instructions for drilling out the flash holes of cases to prevent primer set-back. While it appears that the flash hole on the case you have has been drilled out, it really wasn’t necessary to do that for use with auto pistols, only with revolvers, where any primer set-back jams the firearm up tight, making it hard to open the cylinder or cycle the action, unless one knows how to do an instant fix (putting a wood dowel down the barrel into the chamber and case, and then using it to tap the fired primer back into the primer pocket, which immediately frees up the firearm). They only mention this for revolvers in their literature, so it is unlikely they would have done it themselves with 9mm. In their literature they also advise painting the end of the case so that they would not accidentally be loaded with lead bullets.
I suspect that someone did this for their own use. They may well have done a full box and marked it to the effect that the cases were only for using the Sampson Bullet, prompting your source to remember that they came from a box so labeled. I made up some .45 auto caliber rounds with the Speer plastic bullet years ago for shooting in my garage. At the time, I owned both Colt and Smith and Wesson Model 1917 Revolvers, and made them up for them. They were more fun than using them in one of the M1911s, as you could fire a full cylinder and not have to single load them, like you did in an auto. I didn’t bother to color the bases or anything like that, but I did keep them in a box I labeled for use with the Speer Plastic bullets only.
The one piece of literature I have from Sampson makes no primer brand recommendations, although the Speer plastic cases recommend, naturally, CCI primers, and it is true that in them, other brands often give misfires. I don’t think what I have is an instruction sheet that would have been packed with the bullets, although it has some instructions on it. It is possible that other literature they produced made primer-brand recommendations, so that cannot be completely discounted.
I personally feel that these purpose-altered cases (enlarged flash holes) are interesting, and while I don’t keep every one I run across, I have kept a few in my collection. I don’t think I have yet encountered a 9mm - mostly .45 auto (within the limits of my collection, not collecting revolver cartridges - I have run across a lot of them in .38 special, and factory Winchester copper-coated brass cases with large primer holes in .38 S&W caliber).