Many thanks Reventlov, you have opened a crack in my ignorance of Baltic sword forms and much information is now pouring through!
I have found the following academic writings to be especially pertinent, to have an English summary or be in English and also available on the internet with a little searching:
Kazakevičius, Vytautas, IX-XIII a. baltų kalavijai, Vilnius: Lietuvos Istorijos Institutas, 1996. [English summary from p.125-143.]
Kazakevičius, Vytautas, "On One Type of Baltic Sword of the Viking Period," Archaeologica Baltica 2, Vilnius, p. 117-132 (1997). [English language]
Tomsons, Artūrs, "Kuršu (T1 tipa) zobeny rokturu ornaments 11. - 13. gs.," Pētījumi Kuršu senatnē. Rakstu krājums. Latvijas Nacionālā Vēstures muzeja raksti, No. 14, Arheoloģija, p. 85-104. [Pages 103-104 are an English summary and captions to illustrations.]
https://www.academia.edu/4119215/Tom...an_Swords_2008
Tomsons, Artūrs, "Symbolism of Medieval Swords from the Territory of Latvia During the 11th - 13th Centuries," Folia Archaeologica 29 (2012), p. 145 - 160. [English language]