This is what I'm using:
Code:
// see if we are running Counter-Strike v1.6...
unsigned char *tempbuf;
// only CS v1.6 has this file
// use HL Engine function so that it would not be affected by Steam...
tempbuf = LOAD_FILE_FOR_ME("sprites/weapon_famas.txt",NULL);
if (tempbuf)
{
g_bIsVersion16 = TRUE;
FREE_FILE(tempbuf);
}