[gleeaikin]

Nice maps, but what do the colors mean?

[BroJoeK]

In the map labeled 460 AD, the purple on the left shows what was then left of the Western Roman Empire, while the more reddish color on the right shows the Eastern Roman Empire.

By the map dated 600 AD, notice the Western Roman Empire has disappeared while the Eastern Empire expanded somewhat into former western territories.

My point is: these "guldgubbars" are said to come from Sixth Century Roman Empire military service -- meaning the 500s AD, a time during which the Western Roman Empire collapsed, but the Eastern Roman Empire began with 320,000 lbs of gold in its treasury.
So I'm only suggesting it's far more likely these people served in the Eastern Roman Army than the in the west.

Just seems a bit odd to me the article did not specify which Roman Empire the Swedish pre-Vikings served.