I have a 1970 GTX with a fender tag and build sheet that indicate the interior is P6XA.
I have read multiple decode books and online links that say that is Black vinyl with Charcoal inserts. I even installed repop covers from the reputable interior dealer that confirmed what I had read and sold me the same.
Upon further investigation the “original” door panels revealed a silver welt when the black spray bomb was cleaned off. I believe I have seen a number of P6XA cars with black vinyl seats with silver welts. Maybe they were Black and Charcoal with Silver welts. So what is correct?
Owners of unrestored 1970 P6XA GTXs and Road Runners please chime in.

The silver welt is correct, my 1970 Sport Satellite 4-door also has the P6XA interior. I'll get a photo........

Here you go;

Please show me he seats. Are they simply black with a silver welt?

Black & charcoal with silver welts.

I'll walk out to the shop & get a photo for you.

P6XA;

P - Premium price class
6 - Vinyl bucket seats
XA - Black with charcoal inserts.

Details like piping / welts are not called out by themselves.

P6XA interior here shown with the optional extra cost buddy seat;

the 1970 Plymouth B-body P6XA interior is actually CHARCOAL with BLACK inserts & silver piping

It is also a NO-COST OPTION including the center arm rest "buddy seat" on a Sport Satellite 4-door

E

According to the page at http://www.hamtramck-historical.com/images/dealerships/SalesmansPocketGuides/1970/Pg%20023.jpg

But like many things, original data can conflict depending on the document. Like so many things, not everything agrees all the time.

E here also;

http://www.hamtramck-historical.com/images/dealerships/DealershipDataBook/1970/70_Belevedere0010.jpg

E here also;

http://www.hamtramck-historical.com/images/dealerships/FleetBook/1970/70_Fleet_Plymouth0010.jpg

Like anything though, research & make up your own minds.

here's the color combo charcoal & black* (* black on: dash, carpet, etc.)
http://www.hamtramck-historical.com/images/dealerships/colorAndTrim/1970/70_Satellite0012.jpg

Barry your first link is "Sport Satellite hardtop" & the second, check out footnote #6 - the third doesn't seem to differentiate

but here
http://www.hamtramck-historical.com/images/dealerships/SalesmansPocketGuides/1970/Pg%20022.jpg
& here (footnote 6)
http://www.hamtramck-historical.com/images/dealerships/DealershipDataBook/1970/70_Belevedere0011.jpg
cover Sport Satellite 4-door sedan

is the "buddy seat" charcoal or black?

Look at these pictures you'll see the silver welt, Black vinyl is easy to see on rear vertical and also the Charcoal seating area.
Ron