You can see in these two images that the shirt is extensively embroidered. I have documented 7 different types of embroidery which are used on these shirts. Here is the oldest known skjorte, which I alluded to above.
The arrangement of the embroidery is substantially the same as is known today, and so is the cut, except that this shirt has shoulder insets like in West Telemark. It is easy to see cross stitch and holbein stitch, holbeinsting, in the embroidery. There are three variants of the cut used for this garment, they are shown here in chronological order, from earlier to later. Notice that the shoulder inset is no longer used.
The skjorte of the early 19th cent.generally have no cuffs, the embroidery being done directly on the sleeve ends, as in the above example. Later the shirts were made with cuffs. For a period in between, for formal occasions, two shirts were worn, one without cuffs being worn over one with cuffs.
Here are a couple more examples of early shirts.
In this one above, we see satin stitch embroidery, but of a somemwhat different style than that seen later.
In this example, the collar is executed in typical East Telemark satin stitch, plattsaum. The front panel is executed in three techniques, from the opening out: needleweave hemstitch, uttrekksaum, then cross stitch, kross-saum, and counted satin stitch, klostersaum. The sleeve end is done in rosesaum type satin stitch.
There are two more common stitches used in this embroidery. Darning stitch and gobelin stitch, gobelinsting. Here is a collar which uses darning stitch, smøyg, alone.
Here is an example from 1818 with modest embroidery.
Here above is a sleeve end embroidered in uttrekksaum. The next few images show that the shoulders were also sometimes embroidered.
Some online resources:
another couple, the girl in the revived Beltestakk, the boy in some odd hybrid costume.
Blog of a woman who made a beltestakk, in Norwegian with photographs.
Norwegian costumes are readily available, if expensive. Do a search under Husflid or Heimen,
with the name of the costume in which you are interested. Here are a couple possible sources.
Aagot Noss, 'Draktskikk i Aust-Telemark', Oslo, 2010
Kari-Anne Pedersen, 'Folkedrakt blir Bunad', Cappelen Damm, 2013
Bjorn Sverre hol Haugen, 'Norsk Bunadleksikon' Oslo, 2009
Kjersti Skavhaug et al, 'Norwegian Bunads', Oslo, 1991
Heidi Fossnes, 'Norges Bunader og Samiske Folkedrakter', Oslo, 1993
Ellen Scheel et al, 'Bunad-Brodering', Oslo, 1997
Janice Stewart, 'The Folk Arts of Norway', University of Wisconsin, 1953
Guvnor Traetteberg, 'Folk Costumes of Norway', Oslo, 1966, 1976
Thorbjorg Ugland, 'A Sampler of Norway's Folk Costumes', Oslo, 1996
Laila Duran, 'Scandinavian Folklore vol I - III', Sweden, 2011-2013