Here are my 8 hooded sets (1958, 1959, transitional 1959, 1960, 1961, 1962, 1963, and 1964). The 1958 and 1959 types are similar to each other, the transitional 1959 through 1964 types are similar to each other. There are minor production differences within both groups. You can easily identify the earlier type by looking for slash chest pockets and three buttons for the trouser leg pockets. They used a variety of different metal and plastic buttons, but not the typical plastic pebble type used all the way through 1990.
I've found that there's basically three types of cloth; soft/thin cotton (1958-1960), thick cotton, wax impregnated thick cotton. There's a lot of varieties in the colors, even when new, but soft/thin cotton type is distinctly different from the others. The other two major varieties appear to be one that favors a light brown and another that favors a very dark brown.
The drawings for all patterns appears to be the same, however a few have more detailed blue/green "blobs" than the others.
Extra 1958-1964 trousers. You can really see the difference in the colors. Note the one on the far left has internal leg pockets with exposed button flaps. *NO* idea what that is all about and the date is not readable. It's in the the thin cotton and metal buttons of the 58/59 sets but has features consistent with both the Experimental 64/65 type (two hand pocket flaps) and the 1965-1970 type (internal leg pocket with two exposed buttons).
Front and back of the three types of hoodless jackets I'm aware of (experimental 1964/65, full production 1965, 1966-1970?):
For the hoodless jackets notice that the one on the left has no chest pockets, the one on the right doesn't have foliage holders on the back. There are other differences, but those are the tipoffs.
I forgot to take pictures of the trousers. The Experimental 64/65 type has external pleated pockets and hand pocket flaps, the other type has internal leg pockets with two exposed button flaps with no hand pocket flaps.