Bizarre Canal Zone Overprint Errors...

It's not a Z for an N but a sideways N I think.

How many are actually genuine?

If you know what old individual letters of type look like, then the sideways "N"s are impossible without trimming them and adding spacers top and bottom. Canal Zone errors are also very well documented; sorry, this error doesn't exist in real life.

Could we see very large scans of a couple of these?

Looking at the angles of the overprints on some others, they are clearly not genuine as well.

I really have no idea if they're genuine or fake... I've never
really seen any Canal Zone errors for sale out there of any
magnitude to speak of, so would there be any motivation to even
fake them?

I've had these as part of an estate sale back in 1997 and have
been sitting on them ever since.

Back in late 2014 I had put them aside along with some other material
with plans to send them to our dearly departed friend, Bill Weiss, and
here, they still sit, and I'm unsure whether to send them to APS for
examination, or just keep them here and forget about them.

Larger scans? ~ Sure... probably not until the weekend, but I will be
very happy to upload them... given SCF's 200K file limit, I had to
cut the image size down from the 600dpi large scan I originally made.

Here is one major Canal Zone sale with many errors. It's a popular area and the errors usually do very well. There is plenty of incentive for faking them.
https://siegelauctions.com/sales.php?sale_no=1099

ok... I can see there's quite a few at Siegel, albeit very few of
which were USA overprints, with the balance being on Panama's own
country's stamps.

My untrained eye cannot differentiate the font from those used on
the actual (non-error) overprints, so I'll have to leave that up
to those whom are more experienced on the subject.

I'll upload the larger scans on the weekend, so everyone can get
a much closer, detailed look, for additional commentary... thanks...