Thanks, Richard and Keith -
Well, I just fabricated a groundglass out of a frosted plastic envelope and did a little test on the front porch. While the viewfinder definitely includes a bit more on the left than on the right, as compared to the groundglass image, there's always more room on the "film" than in the viewfinder. I tried this at a couple of focusing distances and the results were consistent - no cutoff as compared to the groundglass image.
So, I can blame the camera for a bit of bias toward the left side of the scene but, if I actually experience cutoff on the right side, it's gotta be operator error. I don't wear eyeglasses when I photograph, and shifting my eye around while viewing didn't seem to affect the placement of the viewfinder image.
With all this in mind, I'll shoot another roll of film, include a test frame or two, and see what I get...
Thanks,
Gary