there is FAA guidance that allows the use of surplus and salvage parts in the repair and restoration of type certificated aircraft.
Yes, and in Canada too, more liberally in fact. However, for a certified plane, it will still require that the licensed aircraft mechanic sign for the part, and it's installation. If you present a part with an unknown history, the aircraft mechanic may accept and sign for it under some circumstances - he/she is then certifying its installation. But, a whole plane worth of parts would not be accepted without authoritative certification.
My previously fully certified FAA TCDS airplane was modified with a different engine and propeller, both fully certified at the time of installation, and installed in accordance with data provided by the original airplane designer - but it was never STC approved. I moved the airplane into the Canadian "Owner Maintenance" category, which permits this change, and it was accepted by the authority, and so registered. It has flown since 2008 to this day this way. The FAA denies it entry into US airspace, as it incorporates [certified] parts, not certified for that type. I was actually once paced for 45 minutes by a US Border Security helicopter (flying on the US side), while I flew along the Canada/US border, always wholly within Canada - the FAA takes its restrictions very seriously! My airplane, which does not qualify as "certified" any more, may be repaired with undocumented parts if need be - but, you still could not build a new one that way, it had to start with a full C of A, and have been flying airworthy, to be eligible for entry into this category.