I don't know how "official" they are, but International Tartans has a series of national tartans. The Swedish and Finnish tartans are listed in The Scottish Register of Tartans. According to the notes in the register, those two tartans can be used by anyone who has obtained the designer's consent.
The designer's contact information:
info@internationaltartans.co.uk
Disclaimer:
I have no experience with that company or designer. It's just what I found by searching The Scottish Register of Tartans.
Good luck with your kilt construction.
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