Yes, columbiana ssp columbiana is supposed to have 4-6 central spines and columbiana ssp yucatanensis only 4. One of the main differences, according to the description in Reppenhagen is that the tubercles of yucatanensis are a lot slimmer than in ssp columbiana, 4-5mm long vs 5-7mm, so that the plant looks like it has more densely packed tubercles, and consequently spinier than ssp columbiana which looks a bit more open and greener.
Now looking at your plants, I am not sure that there is a huge amount of difference, but that could be growing conditions, light etc.
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Chris43, moderator