Some production cards still show the marks used to align the transfers, although most don't.
Still more show evidence of the erasure of those marks from the plate.
Those marks were at one time on every instance of every card on the plate. *
On the card posted in the original thread, On the right about halfway up is the tiny remnant of the right alignment mark in brown
At left, a thinning of the borderlne where the mark was erased a bit too much
Bottom center the remnant of the lower mark.
Top center, they either didn't have the mark or more likely got the erasure just right.
The other example has no obvious remnants of marks.
The registration between yellow and brown is the same for both examples shown making it likely they are from the same sheet.
Printing brown and yellow together even with red on occasion is not at all typical for production. Yellow would be the first color, Brown would be nearly the last, just before black.
Yellow with a darker color is typical for a progressive proof, even one pulled from the production plates.
A couple examples of progressive proofs
https://cigarlabelblog.wordpress.com...ressive-proof/
https://www.abebooks.com/servlet/Boo...hoCzykQAvD_BwE
https://www.artoftheprint.com/artist...tho_proofs.htm
The group of factory 30 cards is like you say, probably production cards that didn't get the factory change overprint.
I wouldn't call them scrap, because they are essentially finished product with no problems that would make them scrap. I believe they were leftover once the order for overprinted backs was completed.
But the Yellow/Browns from nearly every angle appear as progressive proofs from a production plate. A step that would be necessary to ensure that each plate was laid out correctly.
It's possible but unlikely that they're progressive proofs from an intermediate master. But since they represent a full width group, I would doubt that very much.
I think it's less likely that they're simply unfinished production cards.
*It's possible they used several to create an intermediate master, but I haven't seen proof of that, and it wouldn't be an easy thing to prove. There's also some evidence against that idea.