Sure, the pen body plays a part in the overall writing experience, and the Waverly nib isn’t available in all pen bodies. Right now, the Waverly is only available in the 742, 743 and 912 models if you don’t want to get the 823 model from Tokyo Quill. Personally, I think being able to get a pen in a colour that isn’t black and silver or black and gold is worth the difference in price. That, plus you get the vacuum filling system and the larger ink capacity.
If you are a lefty, you owe it to yourself to at least try the pen out. Go to a shop pen and give it a test run. It might be the nib that solves your lefty writing issues. I don’t not have much problems with regular nibs but the WA has opened up the world of boarder, wetter nibs to me. Maybe it will do the same for you.