Oh that's better.

As far as I have seen/read, the 69-73 Sedan bumper is the same EXCEPT for the two side brackets that bolt to the 1/4 panels.  If you found a really nice Sedan bumper, I believe you can cut the brackets off, flip them (or fabricate) to better suit the Wagon & re-weld back on.

All USA spec 69-72 Wagon & all 69-72 Sedan rear bumpers are the same.  The 1968 are rare & have the license lamp hole in the middle (like the pic you posted).  The 1973 Sedan bumpers have the overrider holes in a different place, cuz the 1973's had the big rubber "Federal" overriders.  If you are not looking to use any of the overriders, just get chrome round head bumper bolts & put them in the holes.

That said, I think you can buy a NEW reproduction Sedan bumper, modify the side brackets & fit to a Wagon................