Interesting read though, for Marantz fans like me. I'm interested in 1980 and older, and it seems roughly correct from my experience of owning many of the Marantz components, and looking at them from the inside of the chassis.
I don't see how a company ownership timeline has much to do with all the different models of gear they produced. Isn't when something was made more of a question of when something was made than who owned the company? Proud Marantz owners and if all the favorites folks want in the timeline don't get mentioned the do in a follow up post.
For when it was built, classic audio has a couple different Marantz build dates on their site. Easy enough to find that special unit, its build date range and compare to the Marantz Ownership Timeline.