Marlin Firearms Collectors Association

Several years ago, I purchased a project gun. Never got around to it and am considering selling it. I believe it is a No. 6. It is plated and the serial number is 28128. It has functioning set trigger and a loop lever. The roll stamp reads "Marlin Firearms Co New CT USA" "Ballard's Pa...

I am looking to buy a lever screw for a Ballard. Does anyone know of a source? Either old or repro will do. Thanks for any help.