That is a very interesting idea! But I can't find any sign of Ola or Ifvar at Båhus in Kågeröd, and I have also checked the movement book and no Ola Ifvarsson or Malm left Kågeröd between when the book started in 1804 and untill 1819 when Ola was married and had a son Johan in Konga.
And I searched the birth records in 1788 and 1789, and also 1795 for a likely Ola, without luck, but at least we might rule that out now!
Only one Bohus Ola Malm candidate so far, Oluf Ifversson, 24 March 1789 in Svarteborg, son of Ifvar Ingvaldsson and Inger Andersdotter: Svarteborgs kyrkoarkiv, Födelse- och dopböcker, SE/GLA/13518/C/3 (1788-1835), Image 5 .
One source claims he died 14 May 1789, but I can't find this record (it should be in the same book).