Frank, Sorry, no picture here, but the bottom of your 4 in 1 is so unique it's easy to spot. The bottom is a 3" deep skillet with the same handle and hammering style as your's. There is a slotted projection opposite the handle meant to receive the tab which is opposite the handle on yours. Your skillet was made by the Lodge Manufacturing Company in South Pittsburg Tenn.. The only other company that made a simiar hammered double skillet with the same style handle was The Griswold Manufacturing Co., but the bottom of their deep skillet will be marked with the Griswold trademark and a 4 digit pattern number where the bottom of the skillet you need is unmarked.
I may have an extra bottom for your skillet so in the next couple of days I'll look around here and let you know.
Harry