So, on my trooper, I have underworld trading. In the missions in which you send your companions out to collect companion gifts, every time so far for me they have come back with a gift with red text that states what the item is and it's level. Am I correct in assuming that the red text means it is better for darker side companions? If so, can you get blue text ones for light side companions from underworld trading? Or am I completely wrong in thinking the color of the text means anything at all?

I think it is just an alert colour. I initially thought I could not use it because of the red text in the same way as "Dark I or Light I" items, but I can use them without issue.