I got the year of the date code on mine
right???

I don't know when they started using Micarta in the last 114 years either, or if they used it for a while, took a break and only used celluloid, other early plastics like Bakelite, Delrin (post 1956), bone, and acrylics, for a while.
The 75's I've seen online until a couple years ago have been bone, Yellow Delrin, and a few in their ... "wilder" ... multi color acrylics.
(I don't recall seeing any with wood covers ... Does or has Case even use(d) wood on any pattern?

)
The lack of Micarta on the 75's leads
me to "think" it is a recent innovation, at least on that pattern.
Honestly, Micarta on a "
traditional" factory produced knife seems to be fairly uncommon. It is much more common on "modern" knives, and some non-folding "survival"/"bushcraft" knives.
PLEASE REMEMBER: I am far from an expert on Case! To be honest, I never heard of Case knives until after I joined BF.
As I've said before, "growing up" in Iowa in the 1960's and 1970's "Case" was farm implements. (The latter half of the 1950's I paid attention to and knew a bit about firearms, but not knives.)
I do not recall any ads for Case Knives in my
"BOY'S LIFE" magazines, or my dad's
"FIELD AND STREAM" and
"OUTDOOR LIFE" or any of his gun magazines. (I am sure Case
did advertise in them, just not in those distributed west of the Mississippi River.)
I do remember ads for Western (primarily the L/F66, and W48), Marbles, Schrade, Ulster, Camillus, Remington, Winchester, and Utica. in those magazines)
After I moved to Southern Cali in 1975 to my returning to Iowa in 1980, I did not see ang Case knives in any store I visited in the San Bernardino/Fontana/Ontario area, including the knife store at the big mall in San Bernardino, or the weekly San Bernardino Orange Show Swap Meet, held at the Orange Show Fairgrounds, which I attended weekly for at least 3 years.
Growing up, we had all the Imperial-Schrade brands, Marbles, Utica, Western, Queen/S&M, Frost, Mora, and some "Made in Japan" brands to choose from ... and Remington, Winchester, Colt, and Browning, which my step father said to avoid, because (quote) "They know how to make guns -
not knives!" (end quote)
(YES!!! He
was a fool about more than two things. Another was "Archery isn't good for hunting deer or turkey!" ... tho he did have a recurve bow and arrows with broadheads for hunting.

... I
think he took his Iowa whitetails with a 12 guage Remington 1100 using slugs. Centerfire rifles were prohibited for deer hunting in Iowa. As far as I know, they still are.
He used one of his rifles when hunting deer on his father's farm, somewhere in MO. I don't remember what city it was near. He only took me and my brothers there once, to help with the haying, when I was 13 or 14 ... maybe 15? (I decided "If I
ever do this (haying) again,
I'M GOING TO OWN AND DRIVE THE
TRUCK!!!" 
... I did, too.


)