What year did Jock build the Southfork mansion? What house did he and Ellie live in before that?

When they married, they always lived on Southfork. Southfork was originally founded by Ellie's Grandfather Enoch and it was inherited by Ellie's father Aaron. When Aaron died it was supposed to go to Ellie's brother Garrison but it went to Ellie when Garrison faked his death. During the Great Depression Jock saved the ranch from bancrupcy. As for the mansion, I'm not sure what year Jock built it but it was mentioned that another house once stood on Southfork. I think it burned down in a fire. I used to own a book which had the whole Dallas backstory but I don't know where it is anymore.

If I'm not mistaken, the Dallas movie about the beginnings from around 1986 showed the Southworths living in a mansion. Is that the one that burned? Also, in season 1, Ellie's brother gives her a picture of the original house from Southfork, but it just looked like a normal sized farm house.