Red Baron Returns,
I'm not sure if you want to see the original colour or know of a modern equivalent but hopefully this photo of original fabric in the Australian War Memorial will help.
Allan Teolle has conducted a thorough study of the port side fuselage cross at the RCMI in Toronto as well as a number of other pieces including an aluminium sample (red directly over the aluminium). A conclusion of his is that no streaky camouflage was ever applied although it has its normal under surface blue. It seems that this aircraft was built specifically for MvR.
My speculation is that on delivery it would have been red on all of its upper surfaces with standard stencilling and national markings (large cross fields) with blue under surfaces returning 20mm over the upper surfaces.
Langdon