IIRC it only worked like that if you had the race pick Uncreative. Normally you got to pick which tech in the category you wanted to research. So you could plan ahead if you were going with particular strategy (like Darlok spying with all the spy techs).
But Master of Orion 1 did have a somewhat randomized tech research series.
Yes, you're right, I misremembered. Most races got what they selected. But only being able to select one at least limited what you could research.
Uncreative races got a random one in the category they chose and Creative races got all items in the category they chose. It was far too simple to play as a creative race, such as Psilon.
But Master of Orion 1 did have a somewhat randomized tech research series.