Lovely idea, but I think it is unlikely.
The Vikings "believed in" (that is, their mythology included) an 8 legged horse called Sleipnir; a pair of ravens that could fly across the world and back every day; a serpent so large it could reach all the way round the world and grasp its own tail; a giant wolf; and various elves, dwarves, frost giants, dragons, and many other extraordinary things. Some of these were described in detail in poems and some appeared on coins and jewellery or were represented in pictures or figurines. This does not mean that any of them literally existed.
If one were to argue that the representation of dragons on the ships was evidence to support the idea that dragons/seas serpents existed, then it would be inconsistent not to argue that images of Sleipnir on coins are evidence that 8-legged horses existed, or that representations of Yggdrasil were evidence of giant trees far bigger than redwoods.