My round does not have a two-toned tip marking although it does look like it from the picture. The lower portion of the projectile is slightly rough, almost as if it has been machined, while the upper portion below the orange tip is smooth GM. Interestingly enough, the projectile attracts a magnet only over the rough section.
Mine is headstamped K48 20 \ GE4723 /. Ron Fuchs’s book lists it as API but notes “this rnd has been reported as both API or Incendiary”.
Edited to add:
In Military Small Arms Ammunition of the World, 1945-1980, Peter Labbett shows a list of current (1980 publication date) Swedish color codes which include:
Incendiary: orange bullet tip
Armour-piercing incendiary (12.7mm calibre only): yellow bullet tip
In Tout savoir sur les cartouches: Identification par leurs marquages colorés, Tome 1 Vol-2 (1981 publication date) Philippe Regenstreif lists the following Swedish color codes for 12.7x99mm:
silver/black: EX-P-I (APHEI)