Pinholes under shrink wrap of "vintage" vinyl: any ideas?

[unknown pleasures]

So I've come across a few albums over the years where there's mysterious pinholes in the corner underneath the shrink. I first spotted this on an old Alfred Hitchcock soundtrack I bought years ago where I noticed about a dozen small pinholes on the top left corner but the album was still sealed and the shrink itself didn't have any markings. I first thought maybe it had been opened over the years and someone re-sealed it but it was pristine when I did take the vinyl out after purchasing, and in subsequent years I've seen a few more of these types of marks under the shrink - always a small cluster, always concentrated in one or more corners and always on albums from the 60s.

 

Anyone have any idea what the deal is? I suspect maybe they're primitive promo markings of some sort before they started doing stamps or cutouts, but it's weird it's always beneath the shrink when I see them.

[Plarocks]

On 10/29/2017 at 8:02 AM, unknown pleasures said:

So I've come across a few albums over the years where there's mysterious pinholes in the corner underneath the shrink. I first spotted this on an old Alfred Hitchcock soundtrack I bought years ago where I noticed about a dozen small pinholes on the top left corner but the album was still sealed and the shrink itself didn't have any markings. I first thought maybe it had been opened over the years and someone re-sealed it but it was pristine when I did take the vinyl out after purchasing, and in subsequent years I've seen a few more of these types of marks under the shrink - always a small cluster, always concentrated in one or more corners and always on albums from the 60s.

 

Anyone have any idea what the deal is? I suspect maybe they're primitive promo markings of some sort before they started doing stamps or cutouts, but it's weird it's always beneath the shrink when I see them.

Pics?