Yes—if the adapter positions the lens at the correct flange distance, it should work fine regardless of focal length. In general, flange distance must be accurate if you want proper focus across the full range; if it’s off, you can lose focus at some distances, including infinity.

For Contax RF and Nikon S, one community answer notes that the flange distance is listed as the same, which suggests there may be no practical issue. Another user reports actually using a Nikon S-mount adapter with this type of lens and getting correct focus.

The main difference with some of the more expensive adapters is that they may include an extra focusing helicoid. That can be useful for some lenses, but for a 135mm lens it may not be necessary.

So the safe conclusion is: a simple Nikon S adapter can work for a Contax RF 135mm on a Fuji X-E1, as long as the adapter is correctly made. The long focal length does not remove the need for correct flange spacing, but in this case users have reported success.