Cal Holden submitted the following detailed information on the Mariner Pins

There are at least 5 or 6 varieties of Mariner pins that were made as they
changed suppliers and contended with wartime metal shortages.

These are all different and official:  Remember they were all sterling, at
first.

With dimples all around:
    A. Marked sterling with hallmark R for Robbins Co. N. Attleboro MA
Trefoil 11.0 mm tall with shield approx. level with the rest of the
trefoil surface.  Horizontal rotary clasp.

    B. Not sterling but, well made.  No hallmark. Trefoil 11.0 mm tall with
shield level with the rest.
        Horizontal safety pin clasp.

    C. Pot metal with Lyon Brothers hallmark, cheaply made.  Trefoil 11.4 mm
tall with shield raised above the rest of the surface.  Horizontal
safety pin clasp

With just one dimple:

    D. Marked sterling with R hallmark.  Trefoil 11.0 mm tall with shield
level with the rest.  Rotary clasp.

Smooth surface .

    E. Punched out of sheet metal but may be sterling.  this is a wartime
variety.  Trefoil is 12.2 mm tall and shield is raised.  Rotary clasp.     
     
 

Note from Cal Holden: In the wartime catalogs of 1944,1945, and 1946 they show two mariner  pins.
One is the flat one with no dimples or surface texture in sterling at $0.90
plus 20% excise tax.  The other is one offered only during the war made with
a rayon design on a shield-shaped pin.  It is only $0.30