You are correct. The service manual has a distinct lack of specific information here. Unfortunately, there is a second book as well, the Diagnostics Manual, which we don't seem to be able to find anywhere. (you can find them on ebay, if you want to buy one....)
I only have RWAL on my truck, and the solenoids are in a little block, down by the drivers feet, below the master cylinder. Now, bear in mind, I am basing this off of what I know about GM anti-lock systems..... but, on those, all the solenoids, pump, etc, are in a self contained unit, that the dealer does NOT service. If it fails for any reason, the whole thing gets replaced. If you are SURE that the rear solenoid block is a separate piece, just follow the rear brake lines. Gotta be on there somewhere.