MIL-W-46374E published on 31 May 1989 brought significant changes to the design of the dial. Most noticeably is the new font and the use of the Tritium vials instead of Tritium paint. The Tritium vials are arrange like spoke ends. The MIL-W-46374E were only in production for 2 years. Quickly followed by the MIL-W46374F specification. Thus making these watches slightly more scarce.

The Marathon MIL-W-46374E watches were also issued with a different NSN number. These watches come in Red Boxes and are issued only to special forces. These Red Box Marathon came only in limited quantity.

NSN Number

Quoted from MIL-W-46374 Information Site regarding NSN number:

"Most, but not all, MIL-W-46374 issue watches have an important 11 or 13 number code inscribed on the caseback of the watch (e.g., 6645-00-952-3767). This is known as the "FSN" (Federal Stock No.) on older watches or the "NSN" from 1975 until the present. This code begins with the four-digit FSC (Federal Supply Classification) code 6645 that designates "Time Measuring Instruments". Every watch issued since the 1950’s, as well as stop watches, clocks, timers, etc., carries this designation incorporated into its NSN.

The National Stock Number (NSN), has a two number "country code" following the FSC "6645" on the National Stock Number (NSN). So a newer (1975 and later) NSN would read, "6645-00-952-3767", but an older FSN for a similar watch would read, "6645-952-3767". This two-digit country code is formally known as the NATO code for the National Codification Bureau (NCB). All US issues have either a 00 or 01 country code in this spot. Examples of other country codes that might appear on military issue watches are: 21 for Canada, or, 99 for the UK.

The final set of seven numbers called the National Item Identification Number (NIIN), designates the specific item. This is similar to what is known as an SKU (Stock Keeping Unit) in the civilian retail world. The NIIN designates a particular item usually required to be made under a specific military specification (although not always) and adding specific requirements of its own. For example, the NIIN 066-4279 designates watches made under various specifications but limited to watches that hack and have a high quality movement with 15 jewels or more.

The NSN and FSN are important to collectors of issue watches because they provide more specific information about the quality of the watch in question than the mil spec alone."