Scott,
From what I've seen with "lower" versions of Inventor opening files with piping, wiring, etc created in higher versions of Inventor (Inventor LT versus Inventor Routed systems) has been you will or should see the piping models, but you won't be able to edit them. I can't recall what the error states, but you'll get one if you attempt to do such.
Users should also have no problem measuring the piping in the assemblies.
Hope this helps.
Feel free to contact me if you need more info or need help.