Gee, that's easy for you to say from retirement. If I had thought that way after getting hired at Panam, I would have not had the documentation to get my next three jobs, incuding Fedex. After all, Panam would never go out of business.

Log everything. That being said, Second Officer time is logged as FE, and is only useful to a carrier that has FEs (NWA, FDX, UPS, many non-scheds) , but it does prove what you were doing during that time, and a major will want to see either a logbook, or company records.