The bottom portion is the correct way. Gasket extended. However if the gasket is tight to the slide wall it probably won't leak, either way.
Coat of wax on the wall, clean the gasket and apply silicone spray will probably correct that situation.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.