"The A/R balance per the GL is correct only the AR aging is not."
JE don't Age. They don't have Terms or Due dates. They just sit there. If they are Applied, they don't show as Open. If they are not Applied, they show as Open. That is All they can do for you.
"There appears to be a great deal of journal entries booked over a two year period (2003-2005) to adjust A/R to the accurate balance."
It's always the Wrong Tool for this.
"I need to adjust the customer detail / A/R aging only. It appears all the payments were received against customer accounts but an invoice was never created."
Yes, I covered everything I would do if this file was in front of me.
"They recorded the sales with a journal entry."
That isn't Sales. That is a Manual Entry as income.
Here's the First Thing: don't make More JE. Don't make it Worse.
Here's the Next Thing: You cannot adjust AR without using a name, even if that is a generic name.
Here's the Next Thing: You cannot apply anything against anything if the Names Don't match. A JE for a generic customer cannot be applied to a Sale for a Real Customer, if that is AR; or vice versa.
Here's the Final Thing: You would be able to Apply them to each other if there was a Name in the Income JE for the AR line. If there is not a name, they didn't use "real AR" and that means, you can create an Other Charge Type item linked to that Other Current Asset account and put that on an Invoice for the customer now, dated historically for that JE. Apply the Available Credit to the Payment. Now you are Clearing that Other Current Asset Balance and applying the Negative AR from the checks. I gave this info, based on what you told us.
