They are awkward to offer up if I remember The left one in pic is o/s/r and the other is n/s/r Good luck
They slow down your bumper rotting out from mud trapped between the irons and the bumper by deflecting the muddy field flying up as you bounce across it. I made my own out of some stainless sheet.
.... there's me thinking I'd be fitting everything in the photo, when the irons are already in place .... DUH! "This tool needs sharpening today" By the way you have PM re seatbelt brackets .........
I think the stock late bumpers also have the fixing holes. Certainly both my original and repro bumper have the holes underneath in the right places.
I've never seen them on lates, only on splits and early bays like here https://www.vwheritage.com/211707366d-right-hand-rear-splash-guard-vw-spare I'd be interested in seeing some on lates if they are available.