I used the slide plate from this machine on the 1925 model, since I wanted it to be as close to original as possible. Here you can see the difference between the reproduction plates and the original ones. The new plate, on the left, is sort of burnished, not shiny like the needle plate. And, it'll flip right off of there, if you aren't careful.
I think a piece of an old credit card and some carefully-applied tape would work as well!