Actually, after re-reading the sentence I think it would have sounded better to use the present tense 'is' and then we'd have avoided the question altogether, but in any case, in my opinion it can be either- and I found this to back it up (in case Frank doesn't think I'm expert enough):
The were form is correct at all times.
The was form is possible in informal, familiar conversation.
Examples:
If I were younger, I would go. If I was younger, I would go.
If he weren't so mean, he would buy one for me. If he wasn't so mean, he would buy one for me.
I wish I weren't so slow! I wish I wasn't so slow!
I wish it were longer. I wish it was longer.
It's not as if I were ugly. It's not as if I was ugly.
She acts as if she were Queen. She acts as if she was Queen.
Here's the link if you want to learn more:
http://www.englishclub.com/grammar/verbs-subjunctive.htm
URL:
http://able2know.org/reply/topic-192912