Yes, it will.
The RAW file has a small jpeg file embedded so that you can view it on the LCD on the rear of the camera. That's what the Epson will display. So, just as you can see the image on the rear of the 5D when you're only shooting RAW without a jpeg, you can do the same with the Epson. However, it will be a reduced resolution image as it's only enough for the Canon's LCD.
Thank you for your excellent and concise answer.
Actually, I suspected that to be the case.
BUT, I had not thought about the fact that the embedded jpq would deteriorate as it is "enlarged" by the Epson.
So, I guess the best thing to do, if I want to use the Epson in the field for editing,
would be to shoot raw+jpeg. I had not wanted to do that because of larger files & slower writing. Would you think that raw+the-smallest-jpg would be sufficient for field editing on the Epson ? Thanks,Ken