Out of sheer curiosity I would probably see what the pH is. If it was below 4.5 I might taste it.
Any idea if the beer is fully fermented? If it had been left at ambient temps, I would think it would be safe by now if the pH is below 4.5. IIRC, the mad fermentationist said after 3 months a wild fermented beer should be safe. Googling his site, I didn't see where he said that but you might be interested in this article: http://www.themadfermentationist.com/2011/05/american-lambic-spontaneous.html
If it tastes OK (spit don't swallow), consider adding fresh wort so you have a 1/2 gallon to 1 gallon of this stuff. Let it ferment at room temp for several months. In the meantime confirm if what I remember about when it is safe to drink these things is correct.