Below are assorted images of American medals illustrating original period naming & numbering styles.  The attempt is more a photo essay than text.

US Army Campaign medal No. prefix numbering.


US Army Campaign medal M.No. prefix numbering.

Plain numbering on campaign medals





Army Civil War Campaign Medal

US Navy Civil War Campaign medal numbering.

Campaign medal rim engraving.  Officially done by order of the Navy.  Typically slanted capitals done on either side of the number.

Impressed naming on a Sampson medal.

Navy Specially Meritorious Service Medal

USMC Good Conduct Medal engraving.

US Coast Guard Medal engraving

1930's Purple Heart hand engraved naming as issued to WWI (and earlier) recipients.

The medal, shipping box, and medal box.

Typical WWII US Army hand engraved medals.




Typical of the pattern engraving found on Silver Stars, Legion of Merits & Bronze Stars.



A late pattern of WWII naming


An engraved WWII Distinguished Service Medal


Below shows post WWII pattern script engraving.
Generally attributed circa 1948 as seen on awards sent out at the wars end such as CIB conversion Bronze Stars.

Early WWII pattern official USN engraving.

Late WWII pattern official USN engraving.

WWII era hand engraved DSM / LoM pair

Korean War Silver Star

 

Circa 1970 official naming on an Air Force DSM & Legion of Merit

 


Notes on Vietnam War era engraving styles 
Images & info on the engraving styles found on US medals of that period.