Had an interesting response to my query to Epson about the P800 Cyan cartridge that was packaged with my refurbished 3880:
[I]Thank you for contacting Epson regarding your Epson Stylus Pro 3880. It is my pleasure to respond to your inquiry.
The P800 printer is the replacement printer for the 3880. They do use the same ink cartridges so you can use the Cyan you received.
We take your satisfaction seriously and hope that we have helped resolve your issue. If you receive a survey from us, we would greatly appreciate if you could take a few minutes to provide us with feedback about your support experience. Your ratings and comments are extremely important to us.
If this did not resolve your issue, please reply to this email for further assistance. If you have a different support issue, submit a request via our U.S. or Canada Support Site and we will respond in a timely manner.
Thank you again for contacting Epson.[/I]
Looks like Epson support doesn't know their printers very well.