MangoT21's Beefed Up Replicator Extruder Bracket is quite nice. On his Replicator 1, he found that he needed to move the filament guide holes backwards 0.1 inches; whereas, on my Replicator 1, I found that the original guide holes were correctly centered for my extruders. Consequently, the holes on MangoT21's bracket were a bit too far back for my Replicator 1.
This derivative is therefore MBI's original Wire-Filament Extruder Guide.SLDPRT model with the filament guide holes unmoved but reduced to a diameter of 9.5mm. Then the result exported from SolidWorks as an STL.