Can you hear a difference between the two? I suggest you hook up the pres and do recordings both ways before you get the answer. (I don't know the answer.) If you can't hear the difference that will tell you something. If you can hear the difference and it turns out the signal path was the same that will tell you something else.

As far as I know the two inputs 1&2 on the rear are the same as the center 1/4" neutrik input on channels 3-8. Where as the front two 1/4" neutrik connectors (channels 1&2) are not supposed to be used for line level inputs but for low level sources e.g. guitar/bass pickups. The manual says "that the line level inputs are for things not generally requiring preamplification". I read this to mean not that using these jacks bypasses the preamps just that it has a gain structure that has been lowered.

Try Bob's suggestion just keep the Ramsa signal as high as you can without distorting or clipping and the Firepods as low as you can (almost off if possible) and see if you are getting a good signal at the DAW.

I know for a fact that things plugged into the line level inputs gain can be boosted by turning the knob so it is definitely not true bypass.

You can also ask in the tech forum at Presonus. Rick Navqi usually answers these questions in a day or two, it is faster than emailing them. He helped design all this stuff so he should be able to give you a definitive answer.

I do this with an MPA gold every session. The gain knob goes from -10db to 10db when working with line levels I think, instead of the 0 to 54db on the actual pre.
Something like that.

I read it in the manual for my Firestudio Project.
Check that first, might be different for the FP, but after the pre it is a line level signal, which is what a pre does.
So use the knob like you are using it for keys or other line level stuff.