yes thats true, I think its a good move by dortmund, because they wont find a similar striker this summer, and they have already about +100 Mio. in their pockets, so they dont need to sell.
it doesn't matter they have bidded his release clause earlier or not, bayern did this in 2012 aswell, but götze refused in that time. In 2012 nobody knew that Guardiola will be the new coach of bayern, then in January 2013 bayern proclaimed that guardiola will be the new coach, after this bayern bidded again and finally götze accepted, then bayern could trigger his clause... its not about how much or how early you bid, its about the player to accept any offer.