Piper Colt child seat STC

I have been toying around with the idea of buying a Colt or a
Tri-Pacer (having just foolishly sold my Ercoupe) and ran across an ad
for a Colt with a child seat STC.
I did a google search, a deja/google group search (on rec.aviation)
and looked at the Short wing Piper web site and found nothing else
mentioning it.

Is there such a thing?
Where would one find it?
Does anyone have the 337 paperwork to do this?

Thanks for the info,
Ryan Wubben
Chapel Hill, NC