update - solved by @fskornia - it's a "presser foot screw".. ha!
fellow sewing machine nerds: i am resurrecting a Pfaff Select 1546 from the dead - a thrifting find last week. after 20+ hours of repair work, the machine is nearly done.
i have one last job: i bought a replacement presser foot attach/release assembly. it's supposed to screw into the top feed as shown, unfortunately the assembly didn't come with the screw! (pic 2, shown in red)
can anyone help me identify the screw? i couldn't find it in either the user or service manuals, and web searches are only showing screws for other machines. it would help to know even what the screw is called at this location.







