AFM files are not copyrightable by the "Copyright Law of the United States".
In § 101 "Definitions" of the "Copyright Law of the United States" it is defined:
"Literary works" are works ... expressed in words, numbers, or other verbal or numerical symbols ..."
AFM files are series of words ("space, exclam, quotedbl...") and series of numbers ("32, 33, 34...").
Example:
C 32 ; WX 250 ; N space ; B 0 0 0 0 ;
C 33 ; WX 333 ; N exclam ; B 93 -12 239 696 ;
C 34 ; WX 333 ; N quotedbl ; B 40 380 293 696 ;
C 35 ; WX 500 ; N numbersign ; B 10 0 488 680 ;
C 36 ; WX 500 ; N dollar ; B 36 -102 464 736 ;
C 37 ; WX 833 ; N percent ; B 53 -12 779 696 ;
C 38 ; WX 833 ; N ampersand ; B 36 -16 788 696 ;
C 39 ; WX 278 ; N quoteright ; B 59 406 219 696 ;
C 40 ; WX 333 ; N parenleft ; B 22 -194 312 696 ;
At first glance, AFM files consisting of series of words and numbers seem to be "literary works". But series of words and numbers are not copyrightable and therefore AFM files are not copyrightable literary works.
Argumentum e contrario (Proof by the opposite)
1) If the series of words "space, exclam, quotedbl, numbersign..." as contained in the first AFM file published in the 1980s were copyrighted, then any of the thousands of AFM files published in later years would constitute a copyright infringement of the first AFM file published in the 1980s.
2) If the series of numbers "32, 33, 34, 35..." as contained in the first AFM file published in the 1980s were copyrighted, then any of the thousands of AFM files published in later years would constitute a copyright infringement of the first AFM file published in the 1980s.
Quod erat demonstrandum
