Well as it is released prior to 1963 it is technically made prior to the Carrera but the term Pre-Carrera usually refers to the larger 2447 sibling from 1945-59.
Here are my two 2447's as a reference

Look at the shape & lugs of these two & you will see the relationship to the first Carrera's.
Please note there are also two register, Valjoux.23 versions , i just cant recall the model designation at the moment.

I think yours is a model 404 - check this link to the 1962 catalog http://www.onthedash.com/Guide/_Catalogs/1961-62_Catalog/?show=P13.jpg
In some ways i can understand your thoughts that your example is a Pre-Carrera but i think the smaller case shape is more directly related the model 2444 as seen in the catalog i linked above.
Lovely little earlier Heuer but not one i would usually label a Pre-Carrera.

Hope this has helped you - Darren