Definition: Given the Question and Answer pair, detect whether the answer is acceptable or not. Denote acceptable answer as "yes", otherwise denote as "no". An acceptable answer is consistent with the context in question, detailed, long, and uses general knowledge of English. Answers that are not definite and suggest a variety of options are not acceptable answers.
Input: Question: Possible Duplicate: "If I was" or "If I were". Which is more common, and which is correct? Is this correct grammar? What if there was a Stack Overflow on Shouldn't it be "what if there were a Stack Overflow on"? 
Answer: Prescriptively, you're correct, this should be were since this is being expressed with the subjunctive mood. Descriptively, I think you'll find both in the wild. In informal speech, most people I know would prefer was in this case (and those that don't are sticklers for the subjunctive). I do think that you are much more likely to see were written though, especially in formal writing. Either form is correct, and the subjunctive forms are far from dead. A more interesting question, I think, is whether or not the subjunctive mood is still being used and if the two forms have simply collapsed together. Is this a meaningful distinction? How could this be tested?.

yes