The more common variant of the Grand Seiko First with carved logo dial that we see is the version with a single piece of metal used for the double index at 12 o’clock, rather than the two separate pieces of metal that we see in the earlier “split 12” watches.
From our extensive database of examples of the Grand Seiko First that we have been able to examine, it is clear that there is some overlap in production between the split-12 and single-12 variants, with caseback serial numbers indicating both dial types being found on watches dating from October and November 1960.
Production of the carved logo dial First with an index at 12 o’clock made from a single piece of metal continued through until July 1961, making it more commonly available (although this term is of course used relatively) than the earlier split-12 version.
Below we provide a detail image of the single piece index found at 12 –
We currently have an example of this reference available dating from the very first month of production, which can be found at the following link –