No it isn't. The value of a stock is based on all future dividends, discounted by risk and some penalty for future returns being worth less than money today.
What is going on in the next two months for asicminer is totally irrelevant.
AM has paid out about 0.6 BTC in divs and that was basically without competition for most of the time. This time around is not going to be as profitable.
So, show us the maths which leads you to think that AM is not currently overpriced.