Yes, but I doubt Rift and Guild Wars use a six core CPU, thus you're not really getting anything for your $25. If you buy the Zosma and unlock, that's a bonus. If it doesn't unlock no problem, you still saved $25 for no reduction in performance. Heck, it probably performs better, being a higher clocked chip and easier to overclock too.
The difference is small and we don't really know all the cool stuff that will come out in the next 3 - 4 years that WILL use 6 cores.
It would suck if they ended up with 960Ts that don't unlock (or 1 that does and 1 that doesn't... spousal gaming PC envy...) and they want to do something that does use 6 cores fully.
If we were over the budget already I wouldn't have a problem dropping back to 960s, but even with the $500 budget for 2 whole cores we are still under by $50 and I don't see a super huge need to shave further atm.
We both have good points, I mean the OP can take his wife out to dinner on the savings, but the guarantees aren't there.