I picked this up yesterday, among several other vintage items, from a small shop that supports a local charity. It's not really "minty" looking, but I believe it probably predates the Criterium listed as the earliest one, at VeloBase. I went there looking for info, but it looks like I might have to provide it, instead, LOL. In other words, VeloBase guys, feel free to use these pics, if you want, all other 3rd party folks, please respect Bike Forums' rules & practices.

Velobase is a wiki, you get a membership and you can add the photos and info... you submit it and it is reviewed. Others can propose amendments to the info. We'd all appreciate you adding your photos and info to the data base.

Ah, I guess I kinda knew that, but forgot, although your explanation clarifies a lot. I might have joined already, but I didn't really follow through as well as I should have. I actually have a few other things here too, that might be fun to share.

The single bolt clamp design your seatpost have was pre-dated by more complicated multi bolt designs, not only at 3TTT, but a lot of other component companies, so I don't think it's the earliest seatpost that 3TTT issued.
Here's a seatpost that's for auction currently at eBay that what I think is an older design that was most likely issued earlier than your seatpost.
https://www.ebay.com/itm/Rare-Vintage...item3a810ff99c

Chombi

Yep, that one definitely looks older. And heavier, LOL.

I've got one of the older style on one of my bikes. It was a pain to set up, and its not something you can adjust in the middle of a ride, but now that its set is just fine. My backside can't tell the difference, maybe I should sell it and buy some of the other goodies I've been watching.

It is younger than the first issued 3ttt seat posts, and cheaper too, not always do things improve with the next model.