Does the C-J PF-R invert absolute signal polarity?

Yes the PFR is out of phase. It does not make a "BIG" difference, however to most audiophiles, a small difference mattters. It may affect some systems more than others. It will probably sound like there is less bass when out of phase. The out of phase bass from the speakers will partially cancel out the bass produced naturally by your listening room

CJ does this, because to get it in phase would require additional circuits, which would potentially degrade the sound.

FYI, Reverse "polarity" on a recording is not the same as the preamp being out of phase. The same that flipping an AC plug reverses the AC polarity, but the preamp is still out of phase. These terms get confused a lot.

The speaker cables must be flipped on Blue Circle preamps also.

A Motif preamp I have in my home office system has the Moving Coil phono stage out of phase. (Same added noise issue if another ciruit is added to bring it in phase.) I need to reverse the polarity on the wires going to the phono cartridge to get it in phase.