if there is sticky brown stuff on it, and not rust as it appears, it could be cosmoline grease, courtesy of the US Army bringer-backer.
p.s. -for atlantia, there were eight excalibur swords for sale on epray this a.m., you might get lucky
if the romans had discovered cosmoline, we'd be awash in old roman weapons in as-issued condition but covered in the most persistant substance known to man.
p.p.s - on dating the lances, there was a show on TV here in the UK about the hapsburg lance, i believe they did not date the lance itself, but some organic material on it (wood in the socket?) as metal doesn't date well with c14 tests. also about half the lance's metal was later additions, the viking wings, the waisted section below the gold foil wrap etc. were confirmed by xray to be later additions, the basic leaf shaped roman style blade was untouched as the present guardians would not let them sample that part. likewise the nail wired to the central incision, i think they did sample a bit of the wire. even if those bits are 700ad, that doesn't mean the rest is. it'd be like saying the mona lisa is a fake because it's in a 19c frame.
when you repair, reconstruct, embellish an old blade when does it stop being the original?