How can I see which block was assigned after data has been collected?

I have a survey and at the beginning the Survey Flow Randomizer randomly assigns and displays one of three priming blocks to each respondent. Each block only contains one "question" which is actually just a text box with a specific prime. When exporting the data, I would like to have a way of knowing which of these blocks was assigned to each respondent (i.e, a variable that indicates it). I realize a way to do this would be to use Embedded Data. However, the survey has been open for a while now and a lot of people have already answered, meaning that any changes I make to the survey would have no effect on the previous recorded answers.
How can I see which block was assigned to each respondent, for all data that has already been collected? I have attached a screenshot of the relevant section of the survey flow.