Thats correct. The original ones were paper with a foil coating rather than a thin mylar. There have been some correct repro paper ones produced, find one with any HP rating and trim it off.
You need to buy a copy of Matt Avery's new COPO book. There's an entire chapter on Yenko Deuces, with many detail photos including one showing the way the air cleaner decal was trimmed.
https://www.copothebook.com/