2002 L200 2.2 leak from thermostat area

[Shrewz92]

I replaced thermostat in our L200, 2 weeks ago because I saw leakage from that area. I tightened down the bolts as snugly as I could, without risking snapping them. Still having leakage from thermostat housing area. Is there supposed to be a paper/cork gasket between housing and base, or another o-ring, besides the one around the thermostat, itself? I saw none, nor any gasket residue between the 2 pieces when housing was removed. I am about to put some Permatex RTV between the two pieces. I could not see a break/crack in the 2" segment of feeder hose going into the housing to account for the continued leakage. It's end is dry, but the housing is wettest where housing meets the thermostat base. What did I miss on the replacement to account for the continued leakage?