Accessing fields which are NOT part of a form

I need some clarification as to what the best practice is regarding this. So, say you have a Django form which has many fields that the user can fill out. Say you also have corresponding fields in the models file, but the models file contains some extra fields that the user cannot modify, e.g. unique reference number. Say also, you want to access these hidden fields in the views so that you can present this reference number to the user.

What's the best way of accessing these "hidden" fields that are created when a valid form is submitted? I was thinking of grabbing the latest entry by date, though if there's concurrent requests at the same time, the wrong data may be pulled?