Swapping Drives | Bookmarks Move via Migration Assistant

I got a friend who’s iMac’s screen “died”, basically it stays black and from what i can tell, something is wrong with the logic board. He has a second iMac of the same model. I swapped the screen figuring out that the screen itself is not the problem. We decided to just move the data over to the other iMac.

Problem is, he has already done the Migration Assistant but he is missing his bookmarks that he saved on Opera web browser. Does Migration Assistant successfully grabs Opera profiles containing the bookmarks or do you have to export it and then import it or transfer using Terminal to access hidden files?

Or should I just swap the hard drives? I know for Windows this is generally a bad idea even if they are running the same hardware but what about for Mac?

Thanks for anyones help!