In that the original chip design team would have known? In my opinion, unlikely, as optimization paths like this have been around since CISC became mainstream and academically since around the 90’s. For ‘Meltdown’ it is more on Intel (and will be fascinating to how they respond to the inevitable class actions), but for Spectre, and the general use of the exploit, (which is inherent in pretty much every device we have today) it’s just more a case that the specialists that design these things were never the sort of people to look at security attack vectors methodically.
It then becomes a question of if Intel or anyone else thought of this but then decided not to say. Given Skylake/KabyLake and recent processors could have done something but didn’t, again unlikely. They could have fuzzed it a bit, but didn’t. The way the Intel board acted when Google informed them sort of indicates that they reacted like they really didn’t know anything (other than selling stock asap).
The Google team that discovered these literally just do this sort of thing for a living. Timing side-channel as an attack vector for CPU execution paths is something they figured out probably because they already have a body of work in Web security timing attacks, so it’s the case where the security people thought about the microprocessor side rather than the microprocessor side thought about security. As Chrome as browser becomes more of an OS in itself, they realized that direct memory access and really accurate performance timers made this possible. Ironic, as the next chrome patch will take out the shared buffer memory access and reduce the accuracy of the performance timers exactly to try to stop people attempting this.
As for a nation state knowing about it, I’d bet one of @BeachAV8R’s dollars that there are enough smart people at the NSA that weaponized this if they could and might have. Very hard to tell.