First, many thanks to all, including Ben Hom, Richard Hendrickson, Al Brown, Frank Peacock, Steve Wintner, Ed Mines and Bob Witt, who responded with information answering my questions about the ERIE 71800-series box cars. I was hoping for a quick, easy project but, as is so often the case, . . .
It appears that the Westerfield decal #3314 for these cars is correct for the period 1919-1936. Westerfield lists a couple of other ERIE decals for single-sheathed cars but in any event piecing of the car number and who knows what else would be necessary. I assume the same would be the case for the Champ decal HN-63.
I found an ad in the 1931 Car Builders' Cyc on page 362 and a photo of ERIE box car 75893 on the next page, both show a Chicago-Cleveland Climax roof. It looks like the Climax roof will be my stumbling block. Ah well, another potential project pushed to the back burner.