Can a mapping set use Input Source without a Value Set?

Summary:

Can a mapping set use Input Source without a Value Set?

Content (please ensure you mask any confidential information):

I am trying to create a mapping set within the subledger application 'Receipt Accounting'. I reviewed majority of the data lines that are available in the Input Source, and I am displayed only two data lines with a default value set, namely 'Deliver to Location Identifier' and 'Deliver to Inventory Organization Identifier'. Does this mean I can only use these two lines in my mapping set? Can I not use any of the other lines that are available in the Input Source and type in my values manually on the mapping set (instead of selecting from a drop down)?