The black or brown grips were both the same part number so no difference to the UKMilitary except that for conformity, had to remain matched for colour according to the V-150 EMER of the period. Which also commented words to the effect that the darker colour (presumably black - but it was really a deep fleck brown) was to allow the manufacturer of the paxolin to utilise a material already in being. Paxolin was a tough mouldable and machinable insulating material used in the electrical industry. So don't be taken in by the dealers telling you that the black grips were special ones for the Gurkhas, Marines or other special forces. Just a stop gap variation in production