Eh, what’s a thread really? It’s a term for us humans.

The difference between two threads and one core or two cores with shared resources?

Nothing is really all that neat and clean.

It more of a 2 level NUMA type architecture with 2 sets of 6 SMP sets of 2.

The scheduler may look at it that way (depending), but to the end user? Or even to most of the system? Nah.

There are observable differences. For example, under HT, TLB flush or context switch will likely be observable by a neighboring thread whereas for in a full dedicated core, you won't observe such things.