Either of those units would be good choices, even though they are significantly higher capacity than you need. At most you probably don't need more than a good 850w unit for GTX 770 SLI, but the 1000w unit probably isn't terribly overkill, especially if you plan to overclock anything in addition to the requirements for those cards in SLI.
Being in Tripoli, it's understandable that your choices are probably rather limited when it comes to hardware, under the best of conditions, and with the worldwide supply chain semi-broken it's even harder than normal to source decent hardware anyhow, even if you're in a normally flooded market which you definitely are not.
Given that, obviously it's hard to say "sure, go with this one" when they are probably used and can't likely be guaranteed, but if that is your only option then either of them was a really good unit when it was new and so long as they do not have problems and are not "tired" out, then either of them would do fine. I'd be ok with either choice. Choose the one that seems to have the least miles on it.