Actually you want water around but not in the pot. You will have a rubber gasket at the front of the pot. The the lens goes between said gasket. There will be a clamp that squeezes it all together so that the entire assembly is water tight.

You may want to float the pot to be sure it is water tight now. Mine developed a leak through the stainless steel which was easily fixed by sanding both sides, opening the hole and applying PC7 epoxy through the clean hole I made and making sure the epoxy stuck well to the pot, inside and outside.

If you are missing parts and considering the PITA you are having with bulb ID and with the corrosion, maybe a new low voltage light may be in order.

If you do decide to go that route, let us know and we will run you though the procedure of fishing the new cord through your conduit.

Another thought, if possible, is to replace the existing sockets with something "standard" and go with easily found bulbs.

If you do use the old pot, shine her up inside and when you set the lens, make sure the lens is aligned with the bottom screw that holds the pot in place.