1960 8th Winter Olympics Label Franking

This is a cover that has been sitting in my collection so long I don't even recall when or where I got it. It's a puzzler to me: the cachet looks to be for an FDC of Sc. 1146, but the label is something else entirely. Would this be considered a local post or some kind of U.N. franking? The small auxiliary marking says: "Postage Paid/in accordance/with Sec. 20/U.S. Code."

Can anyone offer some insight?

https://alphabetilately.org/Oly/1960W.html

Winter Olympics
Official, FDC Section 30?
Only 400 Flown
UN to Squaw Valley

interesting -- not a lot of info, but the most I've seen so far. Thanks!

GregAlex - I have one of those covers, too, and have never quite figured it out. I got it in a box lot of covers I bought at a stamp show many years ago. Here is a scan of my cover:

Linus