Actually no, surprisingly the majority of 'anti-clockwise' clocks were designed in Italy.
Think.
It matters not one iota which way a clock operates (even a digital clock that runs backwards has it's merits). You can calibrate anything in anyway you choose.
Now... Stonehenge... And the Mayan calendar...
Neither PROVE that time passes at the same rate from one instant to the next. All they 'PROVE' is that their construction criteria 'fit' the observed phenomena.
You just don't get it do you?
Try a mind experiment.
An hour is a division of a day. A minute is a division of an hour. A femto-second is a division of second
Invent a division of a femto second. Let's cal it a dfb-second.
We can't measure time in small enough intervals to be able to prove that the interval of a dfb second is constant. if there are 100 dfb seconds to a femto-second then 50 of them could be .5 of an expected interval and 50 of them could be 1.5 of an expected interval.
We would assume that each dfb had a constant rate (since a femto interval always fell at the expected point) but we couldn't USE the femto intervals to prove the constant rate of a dfb because because the scenario I described would still fulfill the expected point of each femto second.
Now, bearing that in mind. Several years pass, We have developed quantum entanglement to the point that we can achieve time travel with something other than wavefronts.
People in that time would not assume that we KNEW and could prove the constant duration of a dfb second just because we could accurately predict the point an hour would fall. They would KNOW that we can't do it because we record the current state of our technical advancement.
The mistake that you are making is assuming that the pre-historic britons and the maya UNDERSTOOD what we understand today. They didn't.
At Knowth there is a 'moondial' that accurately depicts the phases of the moon. It's 5'500 years old.
You might assume that they understood the 'time' equivalent of each phase in the same way that we do today. You would be wrong.
They had no idea that the passage of time 'appears' to be constant because for them it wasn't. They only understood subjective time. They thought the moon took VARIABLE intervals to reach each phase but they knew the phases had a pattern. This told them nothing about time whatsoever.
You are transferring the mindset of modern man onto ancient man.