Following FinCEN's guidance on this specific point may be a bit treacherous.
There is guidance that says cash deposited to an account and later debited to purchase an official check should be shown on a CTR as the purchase of an official check with cash. (Dumb, but true nevertheless.) It would be easy to follow the same logic here.
However, when you send the wire, the travel rule requires you to include the customer's account number if the account was the source of the funds. There, I would not treat the wire as if it was purchased with cash and would include the customer's deposit and loan account numbers. The GL account number doesn't tell anyone anything.
In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.