Not directly, but you can use a script to do both. For many forms that I work with I keep track of the tooltips in a spreadsheets, which automatically generates the code to set the tooltips. For example, the code to set the tooltip text for a field named "Text1" to "Tooltip Sample 1" is:
getField("Text1").userName = "Tooltip Sample 1";
To set the tooltips, I just copy the cells from the spreadsheet that contain code like this to the interactive JavaScript console, select all of the lines, and press Ctrl + J, and the tooltips are set for all of the fields.