I watched large sections of his 1,050 game, and yes about the third girder. In fact, I would say the biggest giveaway that these are pieced-together trial-and-error runs is that his basic approach to the barrel boards is one that would cost any other player massively in points (and lives).
Specifically, the way he often plays the bottom hammer with that third girder run makes no sense. Rather than the sane method of getting to the hammer and staying parked below it ready to grab, he goes straight up to that girder, in board after board after board, to uselessly jump a barrel or two for minimal or no gain before going back down to get the hammer. Nobody who actually knows how to play would ever do this because if the fireball climbs at any point before you get the hammer, the fireball will more often than not block you from being able to get it, forcing you to abandon it, and there goes all your points. But Billy plays this nonsensical strategy over and over again and somehow it always works out for him.
Then there are the maniacally and often pointlessly-risky plays that just never get him killed - like jumping over the fireball at one point on the springs in the 1.047 game (which is never necessary on that board but risks death), parking at the VERY TOP of ladders with fireballs directly overhead that will kill him if they decide to come down (which they never do in his games), failing to keep the firefoxes contained on the left side of the rivet boards just so that he can get more smashes (which never ends up causing a problem), etc.
The games look like somebody who has no clue how to play at 1.1 million pace managing to somehow get all the way to the end by getting impossibly lucky about a thousand times.
Note that his "real" games over the past year look NOTHING like this, are at significanly lower pace, and it took him the better part of a year to reach his old scores. Yet in 2007 and 2010 these were supposedly effortless one-day feats?