Given the age difference (9 yr.) between Lars and Elna, did he have a prior wife?
birth not found in 1782 Mjällby.
no other match in 1783.
Släktdatabas Listerlandet has birth date of 26 SEP 1774, @ Mörby 2:1 and d. 21 OCT 1849 same place.
https://db.lister-gen.se/getperson.php?personID=I15152&tree=treeBirth data appears to have come from:
https://sok.riksarkivet.se/bildvisning/C0058255_00031(very difficult handwriting)
Mjällby kyrkoarkiv, Födelse- och dopböcker, SE/LLA/13269/C I/3 (1771-1800), bildid: C0058255_00031, sida 40
Note that this entry is dated by the baptism (1 OCT); birth date noted within text.
Transcript of witness detail from Listerlandet:
Bondens Pär Jönssons hust: Hanna Lars dott: i Siretorp bar det, fadr: Dr: Jöns Pärs: ibm och Mattis Pärs: ibm, samt Pig: Karna Pärs dott: ibm och Bereta Jöns dotter i Mörby. [Beträffande gudmodern, se Valjesläkten] >> this appears to be the same transcript in DDSS:
http://www.ddss.nu/ddss/birthResult?foddID=475617Household exam. 1803-1814 agrees with the 26 SEP 1774 birth date for Lars.