You surely mean /exec minstermodels.cfg, am I right? :)
Additionally I'd recommend - if one wants to use this as a mapmodel in his map - he should copy the list of mapmodels (data/default_map_models.cfg) and these ones to the map config, removing the entries he doesn't need. Thats important to guarantee the compatibility of the map with new releases containing new mapmodel entries in default_map_models.cfg. The mapmodels in a map could become other ones ;)