As with the Universal Geneve 885103/02 Nina, with the 881101/01 Clapton we find multiple crown styles across its production.
The early version looks like a “shield”, with pointed bottom of the shield, and U within the shield. This version appears up to a 2.47m serial. We do see a single piece in the 2.55m range, so it is possible that there was a crossover period in 2.55m.
In the second design the “U” stands on its own. This version appears from 2.55m and later.
As mentioned with the Universal Geneve 885103/02 Nina Rindt, I have seen discussion around the “fat” Universal logo. This logo is also referenced on Omegaforums via Universal Watch Geneve by Pietro Sala, as in the period for the Clapton (1960s), in between the shield and U-only logos.
However, I believe this is not correct, and rather the design is a later logo (not the 1960 period shown), and is not original to Claptons. As an example, we see the U-only logo on the early Golden and White Shadows with serial numbers in the 2.6 – 2.9 serial range (examples such as 2.6 and 2.97). We then see the “fat” logo on pieces with serials in the later 3.0-3.5m serial range. I only see one Clapton featuring this “fat” logo.
Of course, we also see replacement crowns with either no logo or alternative designs. These are not original to the 881101/01.