I don't think so. I know you can save a copy of data, and even restore it selectively later. I guess if the storage format is simple enough, you could build a save file and then restore, but that sounds fraught with danger and more work than just entering the data by hand, at least for 300 values.
The other approach (also more work for 300 values, but would be worthwhile for a couple thousand) would be to do an HMI script to read the values from CSV and write them to DL or MB memory (since most HMI's don't have native drivers yet), then MOVER to D/N/V memory unless DL/MB is where you wanted it.
**another case where the tabular memory view ("memory dump") with optimized data entry keystrokes will be a time saver**