Well crap, I have about three of those around here, could have sent one. I went and looked too, no brass. If you want one to put in the canteen again, let me know I'll throw it in a bubble wrap envelope and mail it.
I had a 1916 holster here once that was gritty and harsh sounding when I holstered a .45 so I threw it in the wash machine with work clothes and pulled it out after spin. It was clean as new and no more grittyness.