The letter stamping on Dana axle bearing caps are as permanent as any file mark, look closely for how they are indexed. No previous work in the axle could obscure or erase them. The down side of not looking for these marks is if they were installed wrong by the last person in there and you mark them the same way, you will reinstall them wrong too, and so on.. There should be no shims on the outside of the bearing races unless you are running an ARB.

SD