I don't know if you can detect them, but you can edit them.
They live in map_icon_meshes.brf, their mesh is named track so you can easily overwrite them.
A quick test by assigning a weapon model as the "track" does this.
These models are technically assigned to use ground_earth as their material, but are force into using either map_misc or map_track. So you will probably have to edit that texture as well. And a full 3d model does go. . . weird, sometimes. Scale wise.
EDIT:
Did more research with max tracking and a new flat grey map_misc.dds.
The meshes are scaled up depending on party size. On a 2d mesh, this isn't too much of an issue, but with 3d? You can get some very, very big boys. As you can see, age is depicted as a vertex coloration, slowly moving from red to yellow to blue/grey. map_misc is really only used for track, battle_track and battle_icon so you can change that texture, so long as your replacements for those icons are also using that texture.