We've had a Marker numbering feature available for those of you who choose Google Maps for your store locator's mapping service provider, but not for ExpressMaps and Mapbox.
We've now made this available for all three mapping services. You can enable this feature on the Settings page (https://www.storelocatorwidgets.com/admin/Settings) under the 'Map Marker Options' section:
Once it's enabled, the map marker pins on your map will include a number which reflects the position of that store in the store list. So, the first store in the store list will have a number of 1 included on it as shown below:
Some markers won't look great with this feature enabled as the numbers are positioned centered on the marker so it will look better with circular markers instead of markers with off center, pin based markers.