Yes, Christian, it is rare. Overland didn't import many of the early version of C&S number 5. Moreover, this is a one of a kind reworking and painting of the model. The Ridgeway spark arrestor and original tender would date the model to about 1918. I believe that the owner was inspired by this Otto Perry portrait of C&S 5 in Denver in 1918:
The headlight isn't quite right, looks like a modern electric headlight of Santa Fe heritage. And the model doesn't have the pneumatic sanders installed beginning about 1912.
This is what the stock O scale C&S 5 looked like custom painted:
But the listed model is nicely done, and is described as DDC installed. So an opening bid of about $700.00 seems quite reasonable.
Jim Courtney
Poulsbo, WA