Inherited Rayon Stamps, Are They Real?

I've been given several very old stamp books by a South African relative. They are old and not all in great condition. Just starting research and came across info on Rayon stamps. Any chance these may be real? #128591; any advice welcome.

The Orts-Post stamp has all the signs of a genuine type 15 stamp.
Needs a cert, obviously.

The Basel Dove looks like a Fournier fake (Reutersköld nr 15).
It would probably be worth something, but the stamp seems badly scraped.

Response from an AHPS member with particular cancel expertise:

Roger Heath
12:46#8239;AM (6 hours ago)
to me, Richard, Bruce, Paul, Steven

The three with the grill cancel look good based on the cancel. I have no idea about those with the PP.
The one with the straight line "ENGER…" looks good, again based on the cancel.

The Rayon II next to the bottom doesn't look right at all.

The others I have no opinion at all, out of my area without a reference book or certificate.

The Orts-post stamp is position 16.Un-framed cross.type scott no.3.Looks over inked though..
The background work is conform to position 16.
photo litho forgery ?

the 3rd Rayon II is position 35. Again a overinked stamp. Very black inking.
The background work is conform to position 35.
I have doubts though as with the above...

The Rayon II next to the bottom doesn't look right at all
Position 36?

From the original stone:


The problem is without the literature (which exists for all the stamps featured here, I have none), you have very little chances of figuring out what is right or what is wrong (except the Basel Dove above which has the telltale sign of a fake).