ZDaemon ACS Extensions - ZD_GetSkinTopIndex
ZD_GetSkinTopIndex() function
This function will provide you with the top index of the installed skins. The syntax is:
int ZD_GetSkinTopIndex()
See
ZD_GetSkinName() and
ZD_SetMarineSkin() when it comes to retrieving a corresponding skin name from an index, as well as setting a skin based off of the retrieved name.