Stampings on RCA Living Stereo and other LP's?

What is the real importance of the stampings on the RCA Living Stereo (shaded doggies)? 1s/1s as compared to subsequent pressings, as well as the press location?
Is the 1s/1s worth actually more in performance? or is it just a collectible issue/
I think a little of both. There may be some sonic deterioration on later pressings, but I think some of it IS collectibility.

However, in digging through lots of flea markets and garage sales, I DID notice some differences on Mercury Living Presence stampings of the same LP. Noticed it 3 different times. A little more noise, and slightly less dynamics, so it seems. I always cleaned my records with a VPI 16.5, so I tried to eliminate the "dirt" difference.

Never had enough RCA's to really test this out. I just assumed it might be the same; pressing master wears out over time.....