Brandis that showed up last week on eBay - Marty you already put this one in the table, but I wanted to document it here.
https://www.ebay.com/itm/1917-WWI-Brandis-Sons-US-Navy-Surveying-Sextant-with-Box-Case-/173126547032Seller’s response to my query about any numbers
"The number on the arch is 4129. The blue stamped number is 4483. Sincerely, Blue Crab Antiques"
I believe that the “blue stamped” 4483 is the faintly visible stenciled number near the right hinge.
so it would look like we have
Brandis 4129
Navy 1530
In box for Brandis 4483
No Navy number
Odd that the box has a USNO calibration certificate, but no Navy number indicated on that cert.
Ric pointed out the following
Brandis 4129 is 629 sextants later then Brandis 3500.
Navy 1530 is only 12 sextants earlier than Navy 1542.
With thanks to Jim Thompson for his sharp eyes.
amck