DEC card cage plastic rails?

My 11/23+ is currently in a small 4-slot backplane. Said backplane came to me missing 2 of the plastic rail guides on the card cage to get the cards in properly. This isn't a terrible problem during operation for the quad-wide card I've got in there, because the insertion/extraction clamps and the backplane itself hold the card in place just fine once it's installed, but it does make the insertion/removal problem a pain in the ass. Does anyone know the part number of the rails? I've had a devil of a time finding that in the service manuals available. I'd really rather just have a better backplane, but that costs more money than I'm interested in spending at the moment. In a related note, does anyone have a BA23 enclosure they're looking to get rid of? - Dave