The ivory fenders were an option if you wanted the two-tone look. I've seen a few New Worlds with the ivory fenders and it's an interesting variation. Most have matching fenders, but the ivory turns up once in awhile.
Re the shifter - from what I have seen, there seems to have been a transition to the silver-face, solid faceplate shifter in the 1948-49 era. Most of the bikes from that era I have seen were the later shifter. But Schwinn continued using quadrants well after the English had largely moved away from them in the later 1940s. In England, the post-quadrant generation of handlebar shifters appeared before WWII, with the early long-arm and externally sprung Sturmey shifters. Even in 1939 the English were starting to move away from the quadrant. But Schwinn kept using quadrants well after WWII. It certainly could have been moved on from another bike; could have been something someone ordered with the bike at the shop; or original. I don't think we can know for sure. I don't think it's a significant knock on the project, myself.