Overall it shouldn't matter much. They should share the same spec other then clock speed. And 50MHz either way isn't going to matter much. If you want to OC the cards then it might as the coolers and VRMs could be different.
This is a pretty good price for a used card, but make sure you SEE that the card works well. If it doesn't work right in person, it clearly isn't a good idea to buy it.
As mentioned above as long as you trust/believe then it's ok. Keep in mind the cheapest on newegg counting rebate and shipping is around $270. So you are only saving $30 while increasing your risk.
Yeah I get it, but I live in Europe. So i think this is good price not best but good. Thanks on all the answers.
I have one more question. What do you think is this Gigabyte R9 280X REV 2 better than MSI R9 280X Gaming ??
Overall it shouldn't matter much. They should share the same spec other then clock speed. And 50MHz either way isn't going to matter much. If you want to OC the cards then it might as the coolers and VRMs could be different.