I wouldn't pay a premium for it. You're going to have to get it to cross over to PCGS as a 66 for it to even be worth the grading costs.
Crop the slab out of the photos, look only at the coin, and then ask yourself how much you would pay. Without that almost certainly debatable number slapping you in the face, would the coin still interest you? Does it, from what you can see and at any price top of melt, scream "buy me"? If not, perhaps it would be best to look elsewhere.
I should mention, it is not uncommon for private persons who grade and slab themselves, to buy coins in B.U. condition by the roll and bump up the grade by a notch to garner interest in the coin for marketing.
I agree, but will add that you are being overly optimistic when you say that people use BU coins in the holders. They sometimes do, but often the pieces have issues such as cleaning, whizzing, etc., even for common pieces. I have even seen whizzed up slider coins in them. It is very sad.
That GSA symbol bothers me also. Even though it explains the Grader name beneath it would tend to be construed by novices as being from the General Services Administration which is a U.S. Government entity. Bad for the novice and slightly deceptive.
Slightly, nothing... that's the whole point, and such an assumption was made in a fairly recent thread.
First, with an unknown slab, you have to go forward as if the coin were raw. Second, based on those photos, I doubt it would grade anywhere near MS66. Whatever melt value is would be my best guess as to the value.