I've had the honest pleasure of working on original Bugs, Buses and Ghias and have seen pinch clamps like these used everywhere on aircooled cars, regardless of vintage. In addition to securing fuel lines, they were also used on the later cars up in the trunk for fastening down the winshield washer lines and emissions charcoal canister vacuum lines. These clamps are very similar to the originals, however if you look closely you will see that they do in fact deviate from the originals in that they are joined/welded together on the opposite side of the crimp side of the clamp. The overal effect is still authentic and these clamps will definitely find their way onto the Nautilus.
McMaster-Carr sells what you need to equip your car with these clamps. They are one-use items, but if you are looking for a bit of extra authenticity, these clamps are definitely the way to go. One bag will give you enough to do the fuel lines on 2 to 3 cars, easily. They come in different sizes, too, so if you want them for the vacuum lines McMaster-Carr should be able to set you up.