This is a straight forward 1959 Bulova 23 "G". Yellow gold plated case with sunburst dial with stick hour markets. 10BZAC 23 J movement. Stainless back with L9 date code. Replaced bracelet with leather strap.
Save for the expansion band, which I suspect does not affect the variant, the Bulova 23 "G" looks good.
I have found that in 1959 several of the single letter variants adopted the second letter W.
This should likely be the 'GW' for 1959; and also, in 1960 the model ref number changed to 03563.
I'm going to agree with Ken. It's likely this became the "GW" in 1959. What linebook did your initial description come from? Pre-1959?
In reply to I'm going to agree with Ken… by neetstuf-4-u
The reference ad came from page 72 of the 1958-1959 Linebook BAWD0136. Bulova 23 "G" which is most likely 1958. Assuming the second listing on page 121 is for 1959 this does in fact change to "GW". Nice catch and not as straight forward as I thought LOL.