Did The Paper Used In American Banknote Re-Engraved Stamps Change?

This is a question for my education, not about a particular stamp. I notice that the look of the soft porous paper in many of the re-engraved issues (Scott 206-209) looks different from the paper in the earlier soft paper issues. I'm not sure how to describe it, but in general the paper seems more tightly wove. Does that makes sense? Was there some improvement in paper manufacturing or something that happened over time? Do collectors make any distinction of something like an "early soft paper" and a "later soft paper"?

Might be the difference of the sizing agent in the paper.

https://goscf.com/t/44915#381362

That's an interesting thread. It might just be a different paper supplier as well.