Page 81 of Pina's Smoke & Ice shows a blue-gray decanter in this swirling thin ribbed style. So, that supports the online attributions you have found and shows that Gullasruf did do this style of glass.
The precision of the workmanship and the smoke stems and feet of your pieces Connie would tend to suggest Scandi to me. However more hard evidence and/ or more specialized opinion than I can offer, is needed to put this one to bed.