The 14-D looks like it was removed from a bezel, both of the 1906s look undergraded to me, and I would be happy to own any of them!
I just went and looked at the plate coin for PCGS coinfacts and it also has these lines. I learned something new today already!
Yes, they are indicative of die buckling . . . a fairly common occurrence on indian quarter eagles of several dates, but especially so for the 1914-D.
I don't say this often but you did good ! The '26 is the only one that's over-graded. In my opinion of course
Well, as Meatloaf used to say... "I want you I need you But there ain't no way I'm ever gonna love you" So now we can wait for @GDJMSP to sing "Three outta four ain't bad"! ;-)
I have no doubt that it does, but are those 62's really 62's ? Ya see, you can't just look at the numbers on the slabs and assume the grade is accurate. Your own words prove that, for how could a 60 look as good as a 62 ? And when were those 62's graded ? It's truly a complicated situation. When you started this post you titled it as being about coins in old holders. You did that because, you just like most other people accept and believe that coins in old holders would be upgraded if they were graded today. In other words in old holders are a good thing. But what are you acknowledging when you think that way ? You are acknowledging that grading standards have changed, and changed drastically. Some people don't even realize they are doing that, others do. If you go back far enough on this forum you'll find where I used to say that I agreed with the grade assigned by a TPG about 85% of the time. But yet in today's world I will say that the TPGs over-grade, and sometimes grossly over-grade, about 90% of the time. That's a complete 180, in fact a bit more than 180 ! Now my grading standards haven't changed, but the TPG grading standards sure have. They have become much looser and much more lenient. And the fact that you yourself believe that those coins being in old holders is a good thing, proves that you believe the same thing I do ! The same thing pretty much everybody believes, but yet they fail to consider it and take it into account when they compare coins. You asked what I'd grade that coin, OK, let's talk about the coin. Look at it, in particular the obv, but you will see some of it in the rev too. See the black crud caught around some of the legends and stars ? Well how do you suppose that black crud got there ? What we call black crud is nothing more than a combination of ordinary dirt and grime combined with body oils from people's fingers and hands. And there is absolutely no denying that it is there on the coin. But if the coin were truly uncirculated then how did the black crud get there ? That's your first clue that the coin is over-graded - even based on pictures. Now look at the cheek, and the jaw line, and the small area just behind the corner of the lips. See how much darker those areas are, how the luster is broken ? There's even a little bit of it on the hair in front of the headdress. It's pretty hard not to see it. That's wear, plain old ordinary wear. Couple that with the black crud that could not possibly have formed on an uncirculated coin, and you know, just plain know that the coin is not unc ! So what would I grade it ? The wear is minimal, I don't really see much of it anyplace else except for a tiny bit in the fields just in front of the neck, so I'd probably give this one a 58 - based on the pictures. If I saw it in hand I might drop that to a 55, but that's a maybe. In today's world, coins that are graded 60, 61, 62, 63 and even some 64s - are really nothing but AUs. But back then, when these coins were graded, 85% of the time they were graded correctly. That all stopped in 2004, and it has only gotten worse since then, much worse.
It is possible for a coin to get dirty without being worn. Just look at the saddle ridge hoard. Also, the Eagle's shoulder and the Indians headstrap on the headdress are the first places to show wear. Neither of those places are worn.
I told ya in the sentences before that - the TPGs loosened their grading standards. There's a difference between getting dirty and getting black crud on them. And there is no such thing as any specific area on a coin, any coin, always being the first to show wear. Wear can show up first on any high points, or any low points, or anyplace else in between.