Yes, certainly possible.
Use the script step Get (AccountName).
Note that users can change thier own "UserName" so stay away from Get(Username).
If there are a large number of fields to set, consider a table to hold data for each accountName instead of a script.
On each table you need such info, have a calculation field which = Get(AccountName) which links to your AccountInfo table. Now you don't have to copy data...just use the relationship to access the pre-existing data.