Hi, yes, you would need to flip horizontally if you shoot the emulsion side facing the lens. (In Lightroom, go to “Photo > Flip Horizontal”). In most situations, though, you probably won’t see much of a difference shooting one side vs the other.
I think the main reason for having the emulsion side facing the camera is to make sure you’re getting the most resolute image of your film possible. This way, you’re not shooting through the plastic film base, which MIGHT blur or distort the image. But like Nate said, you might not see much of a difference in quality. Probably depends on the film! Experiment and see what happens. Personally, I just shoot emulsion side up just to be sure, because digitally flipping the image is pretty simple!
I did quite a bit of A/B testing on this and couldn’t tell the difference in quality with emulsion side up or down. So now I just shoot the back side so I can skip the reversal step, which is a bit tedious because I can’t automate it with raw files within lightroom (AFAIK).
Yeah, I really haven’t seen it make a difference, either. It’s pretty easy to reverse in Lightroom though. Just select all the images that need reversing, and go to "photo > flip-horizontal. " If you want to get fancy, you can also assign a keyboard shortcut to this (at least on Mac in “system preferences > keyboard settings”).