Yes. Right click the name of the team in Finn's editor. Select EXPORT Team. This will save the team to whatever folder you select. However, this team cannot be used as an Historic team to load in separately like the other historic teams.
You could Import the team into an historic roster set, but you cannot use it on its own to play against another historic team. You'd have to go through an additional step for that:
You could load a single same franchise historic team into Finn's editor, Import the team you just saved to overwrite the loaded team, and then change the year in the editor (also right click name) and resave. You'd have some editing to do for left over players probably from loaded team, and to adjust the depth charts, but you could do it.
Hope this helps...
C