1) Yes, GrandPrixYannick, they do have an armco barrier at the chicane for the 1968 season addon in Monaco (also used in the 1969 season as well). But I'm not sure if we could make a new track directory, monaco68. I guess we could do that.
2) I don't know about the 1968 online mod, but, of course, it would be the same as the 1967X (online mod).
This picture in Monaco has an armco barrier at the chicane during the 1968 season.