Geco I .30 Carbine

The Geco .30 Carbine rounds with the I in the headstamp.
(Geco I .30M1 3 ). Are these from the 50’s or 60’s?
Also, besides 2, 3, and 5, what other years are known?

I rechecked my books, to see if this was a stupid question, and still came up empty. Although not a trick question, it still may be common knowledge, an I have not heard yet. Are the Geco .30 Carbine, with the I in the headstamp, from the 1950’s or 60’s? Or is it something else completely, and the 2, 3 and 5, that I know, of are not the years of manufacture?
I hate to ask the tough questions, on the Dag and Geco date coded Carbines, untill I have the answer of this question. But here goes anyway. The earliest I have heard of so far, is 1968 Geco, and the latest is a 1985 Dag headstamped Carbine. There is also known, (without the date code letters), the DAG 75 and DAG 87, with the headstamp on the bottom, and the DAG 76, with the DAG on top and the 76 on the bottom of the hs. So the questions are, what year did they start with this type date code, (both DAG & Geco), and are they still being made today, or have they changed to the 1987 type headstamp? (And did they skip any years?)
For those who do not know, (and if my info is correct) DAG & Geco used the letters V,T, & L, (at least), and rotate them for different numbers. (On many calibers.) The V = O, upside down V = 1, upside down T = 2, T = 3, L = 9 etc. Someone who can rotate the letters, can make a better list than I can. I collect .30 Carbine, and finally got a few of these from a friend. I have not seen too many of these for sale, so either they are not getting here, or they are scarce. (Or I have to get out more!)
Thanks for any clairifications.

The GECO codes (courtesy of Morten S).

Nice! Thanks Boz & Morten.

After WW2, the Dutch police used for many years the .30M1.

Here are some German boxes from these day

Thanks for the pictures Dutch!
A friend had told me about the center round, and that it also comes with the letter B. It’s nice to have a picture of it, and it’s box.
I have the last box, only with “LOT MEN 83-2”. But I have not heard of any other MEN Carbine headstamps, other than MEN83-1 .30M1 and MEN 70 .30 CARB… Please let me know if you know of others.
Thanks again, sam