Unfortunately, we really don't know much about the tradition of Norse and northern European shipbuilding during this time period (and this is where I'm going to be pedantic and say that "Viking" was an activity, not a noun, though language is fast changing this). The Gokstad and Oseberg ships have been the basis for much of what we know about the shipbuilding tradition and there hasn't been a very good survey written since at least 1950, although I'm holding out hope for something newer.

It would make sense, given the similarities between those two ships and the time period in which they were built, that they could have been the products of a shared base of knowledge for building ships, but we don't know enough to say definitively that they were built in what we'd consider a shipyard (i.e., a specialized location where many ships were built.) Sorry to not be of much more help.