Zenith A386 Caseback

Zenith A386s had one of three different caseback styles depending on batch of production.

There were two designs with plain caseback and a third with “NATO” star. All three versions had different stamping on the inside of the caseback.
The case number for the watch is located on the caseback exterior only, and features a set of numbers with a single letter, in the pattern ###X###. Note that the etching for the case number isn’t overly deep and wide for each number/letter, and if you see this it is generally a forgery.

The first caseback, associated with the Mk1 case, features a plain back and caseback interior with centered text:
ZENITH
SWISS MADE
ACIER
INOXYDABLE
(note that there is no SP number on this caseback)
Case numbers: 538Dxxx – 539Dxxx

The second caseback batch, known as Mk 2, again has a plain back, but with centered text:
SP
1205
ZENITH
SWISS MADE
ACIER
INOXYDABLE
Case numbers: 706Dxxx – 708Dxxx

The final caseback batch, Mk 3, has the Zenith star on back, with text in a circular pattern around the outside edge of the interior of the caseback. There are, however, two different casebacks that can be found in this set.
The first group has the following text:
Zenith at 12 o’clock
SWISS MADE at 3 o’clock
SP 1205 at 6 o’clock
ACIER INOXYDABLE at 9 o’clock

And groups into case numbers:
861Dxxx – 862Dxxx
922Dxxx – 923Dxxx

The second group has the following text:
Logo with M over Z inside a diamond at 12 o’clock
SWISS MADE at 3 o’clock
SP 1205 at 6 o’clock (with a slight gap between the 12 and the 05)
ACIER INOXYDABLE at 9 o’clock

This text may be found in group:
230Exxx – 233Exxx

Zenith A386 Casebacks
The four casebacks found on the Zenith A386

“SP” indicates Spillman, the case manufacturer for the Zenith A386 as well as other models, with “1205” as the caseback for this model. You may also see other incorrect casebacks such as those with “SP 1301”, indicating the caseback was original to a different Zenith model, either a A3817 or A3818.