@RobDrawYeah, you need to execute it, but when you run the Dynamo routine, it will give you a "live" (i.e. CURRENT) view of what is in the model when it runs (and actually, if the run mode is "automatic", it updates as things change - in the dynamo example above, you can look at the preview for String.Join or connect a "Watch" node to "str" output [I can't believe those things are still not resizable] - NOTES: it only opens in Revit 2020+ but you could recreate the graph in previous versions, freeze the "WriteText" node so it doesn't write to the file, and you will probably want to sort the output so you see the sheets in order).
But when you open a Sheet List schedule view, all those manually-filled-in values for "Titleblock" are static - they aren't changing automatically and have nothing to do with what Titleblock is ACTUALLY being used, unless somebody updates them manually or with Dynamo (in contrast to Sheet Number, etc. which DO go "both ways" automatically). You would think it wouldn't be too hard for Autodesk to just make another special type of schedule (like View Lists and Sheet Lists), but it's taking them a while for other simple stuff like filtering by type, etc.