Django model inheritance: share table with parent model -

we use django.contrib.flatpages in our project. @ point, decision made extend django.contrib.flatpages.flatpage model monkey patching 2 fields, which, @ time, didn't seem bad solution. want rewrite subclassing model make bit more readable. however, stick existing table django flatpages this:

class meta:     db_table = 'django_flatpage' 

without creating additional tables, has data (including 2 said fields), , don't want touch database much.

now, question itself. there clean way it? also, should able register model in django admin, if changes anything.