Thanks Reiner!
No, I can't say I've ever heard of the counterjet being observed nor imaged visually. Personally I'd have to think its an impossibility as it would lay, in theory, on the other side of the core.
I did hunt around the internet for a radio image depicting both jets but I did not find one. To be quite honest, some of that radio stuff boggles me and I'm not really all that certain what it is I'm looking at sometimes!
But maybe someone here on DSF with more knowledge than me may know of such an image.