No they'd be the same speed, except the 965 would probably be able to overclock to 3.8ghz at a lower voltage. Nothing is guaranteed, except what you get when you buy it.
Example - My 940 BE overclocks to 3.8ghz with an extra 0.2v. A 965 BE would probably overclock to 3.8ghz with just an extra 0.1v, maybe less.
Also, TDP is relatively meaningless. It's there as a safety measure because it is just about possible that the 965 BE could draw more than 125w. In reality, it won't draw anything near 140w, even with insane overclocks.