IMO, the Fremont $25 is a true counterfit.
Off the top of my head, it could be the only one I know of. Most counterfits are altered chips.
This one was made from the exact blank. If you did not know to look for the subtle differences in the inlay, you would not know it was counterfit.

These were passed at the Fremont. I thinkl it was in the early 60's. I have the dates at hime.