If it really matters to you, you're going to have to research it. Unless it's a classier bike than this one, where you might find Tange Prestige or some other label that has a clear meaning. The 4130 labels were put on mid-range bikes where the designers were pretty cost conscious and so aren't as meaningful. And some factories definitely played tricks with them.

In general though, I think you are taking this a bit too seriously. You're talking about the difference between low-end tubing and a little less low-end tubing. In general it isn't going to make much difference between how the bikes ride.