smog pump air plugs

["Ofarrell, Fergus" <Ofarrell.Fergus@hitco.com>]

Okay listers,
my question of the day.  My smog pump was removed by the PO, and plugs
installed.  But, they were not Tom Walters' plugs (I have since bought a set
from Tom), they were NPT plumbing plugs.  In following the directions that
came with Tom's plugs, what is the likelihood that the NPT plugs have bunged
up the material around the threads so bad that these new ones will not go
in?  I am going to buy the metric tap and cross my fingers, I just wondered
if anyone had experience with this already.
Fergus O