inline 6 integrated head ?'s

[gonecountry]

Might be going to look at a '76 c10 with a 250 and bull low 4 speed this week.
No pics of the left side of the engine so I am wondering if it's an integrated head or not and the owner isnt sure what I mean. I can see it has a flat top valve cover not the big square lumped ones from the 80's

In my searching I cant find an exact year that the intergrated heads came into being

Thanks in advance