How To Restore Deleted Original Residential Lots

Oh- partly, I misunderstood you.

If it's the BASE house, just select "save as" and save your game as a specific file name "mine" for instance.
go back to the main menu

Start a new game.

go to that lot (in the new game) and modify it.

Once you are in "build mode" click on the little file at the top and select "save lot"

Save it to yoru gallery

Load back into your "mine" game

click on the lot and select modify

once you get into build mode on the empty lot, click on the little picture thing in the top right to get into your gallery

click on the house and click the little "add to world" button in the bottom right and place the house.