MB tex has been used for a long long time
My 84 300D turbo is mb tex. You can tell because its not real leather. The smell, feel, touch, looks, etc. MB tex is kind of like plastic/vinyl type texture.
MB tex usually does not crack, although I did make it crack in my 92 300D. Another way of telling is on the piece you plan on replacing, take a terry cloth and some dye removing solution and rub vigorously and if it comes off then its leather. I wouldnt really recomend that method.