The notation on the graphic is for a MK-IX/01 Constitution-class starship. I think the idea for the graphic was to show Khan reading up about the kind of ship he finds himself aboard. If that's what the graphic was meant to convey than at least as far back as "Space Seed" the Enterprise is supposed to be a Constitution-class ship. And the /01 added to the MK-IX might be supposed to mean the graphic is of the Enterprise's primary phaser. The same thinking could be in effect when the graphic finally shows up onscreen in "The Trouble With Tribbles."
As I said before, I guess it might be open to interpretation whether we are to assume that Khan was interested in the Enterprise
and its class of starship or if he was, instead, reading up on other
kinds and classes of starships from other eras that might have been forerunners to the Enterprise
It turns out, there's an answer to the question. Matt Jefferies actually had a set of marching orders: the script. He didn't just create any old graphic he wanted. The script for "Space Seed" actually has a pretty significant line:
"I was once an engineer of sorts. I would be most interested in studying the tech manual on your vessel."
(Note that Khan says that he is interested in learning about "your
vessel," not "vessels that are earlier forerunners and somewhat similar to this one.") I don't know how well Jeferies actually hit this target artistically, but I think his target was clear.)