"What would you have gotten for it, if he had bought it?"
Translation:Hvad ville du have fået for den, hvis han havde købt den?
Yes, of course it matters. When there are mistakes in the course, they should be reported, so corrections can be made. But more importantly, what appears to a learner to be an error in the sentence, may be a lack of knowledge on their part, so instead of just reporting it, they can post their doubt here and possibly learn something new.
In addition to what tvindy says, people in the comments explaining why this is the case helps people who may be confused as to why it's a mistake. I know whenever I get corrected for something and I don't understand why it's wrong the first place I check to try and understand what I may have missed is the comments section.
Other people who have encountered the same mistake can alleviate the concerns of those coming after them.