Project Mercury Era Astro

An early Astro with no handle slabs has come online that might be an early one. It has a canteen snap type safety keeper. I don't think I have seen one in this early a sheath.
I'm not qualified to say for sure, but wasn't this kind of sheath replaced by the brown button sometime in the 1960s?
Any thoughts when it was made?
I haven't seen this knife posted here and I know this community is interested in the older knives so thought it appropriate.
Thank You.

That is interesting. Very nice. Interesting that the top rivets are not the usual large brass rivets as used on many split back sheaths.

Where did you see this Astro?

Hi Ronnie, I sent you a PM.

Thanks, Richard

Also Ronnie, you asked about the rivets. I think the brown button sheath and then the early baby dot Johnson had the large rivets, but the earlier canteen sheath had regular size rivets at the throat. I think that's the way it was from what I observed.

Roger that Richard.
Thanks.