I’ve done a little bit of poking around, and the answer appears to be “yes”. There are dynamic fields defined in the default schema.xml file created by ColdFusion (<CF9_home>/collections/<collection_name>/conf/schema.xml), but they are commented out! So even if you want to index a collection using only dynamic fields, you still have to edit schema.xml to uncomment the lines where the dynamic field wildcard matches are defined:

   <!-- Dynamic field definitions.  If a field name is not found, dynamicFields
        will be used if the name matches any of the patterns.
        RESTRICTION: the glob-like pattern in the name attribute must have
        a "*" only at the start or the end.
        EXAMPLE:  name="*_i" will match any field ending in _i (like myid_i, z_i)
        Longer patterns will be matched first.  if equal size patterns
    both match, the first appearing in the schema will be used.  -->
   <!-- Dynamic Field for CF Category support
   <dynamicField name="category_*"  type="string"  indexed="true"  stored="true" multiValued="true"/> -->

   <!--
   <dynamicField name="*_i"  type="sint"    indexed="true"  stored="true"/>
   <dynamicField name="*_s"  type="string"  indexed="true"  stored="true"/>
   <dynamicField name="*_l"  type="slong"   indexed="true"  stored="true"/>
   <dynamicField name="*_t"  type="text"    indexed="true"  stored="true"/>
   <dynamicField name="*_b"  type="boolean" indexed="true"  stored="true"/>
   <dynamicField name="*_f"  type="sfloat"  indexed="true"  stored="true"/>
   <dynamicField name="*_d"  type="sdouble" indexed="true"  stored="true"/>
   <dynamicField name="*_dt" type="date"    indexed="true"  stored="true"/>

   <dynamicField name="random*" type="random" />
   -->