The spacers in my holster are around 1/2" long and it has two. They look like these in the pic, and are at the area's where the screw's are. First holsters I ever had with these in them. I don't know how long they supposed to last and I always like parts around for stuff that might not last long. If they last as long as the holster then I am good because they are expensive, costing almost as much as the holster did. Thanks
If I was looking for replacements, I might start at the local hardware store (Ace, where I live). They've got drawers full of stuff: rubber stoppers, bushings, nylon or aluminum standoffs, even 'gunsmithing' screws. Back when I was building FALs, I used shaft collars from the hardware store as 'spacer rings' for my Israeli FAL handguards. Fun to see what they've got (for me at least), even if I don't find what I want!
IMHO, FWIW, YMMV, doesn't cost anything to look, etc.