Hello,
Currently on ebay is a photo of a Fokker E.IV of KEK Sivry flown by Ernst von Althaus at:
https://www.ebay.de/itm/Flugzeug-Jag...wAAOSwlRVfzMLa
and two further E types, one an E.IV of the some unit, one flown by Oswald Boelcke (E.123/15?) at:
https://www.ebay.de/itm/Flugzeug-Jag...UAAOSwNM1fzMJG
Regards,
Clint