I recently purchased a vintage big triangle seamaster. However, I’m having trouble matching it with another 563, specifically regarding where the words “unadjusted” are and the jewel count
My 563 has the "unadjusted" above the "seventeen jewels". It is a Seamaster but not a 300.
All the 563 movements I could find look like yours. I've found 550 movements that have the word "unadjusted" below the "seventeen jewels" which leads me to believe that they used the bridges interchangeably