For evolution temples, yes. After 25 you don't get any more bombs dropped. However if you have a bomb producing dragon, what you collect gets added to your stockpile beyond 25. So for those that max out, they can keep collecting up to what I guess is a limit of 1000, however only from bomb dragons and not from evolutions.
Terrible start for me so far. I had a few bombs saved up but I'm averaging under 2 parts per bomb. Am getting 3 parts sometimes, but also failing with just 1 part about an equal number of times too >_< Usually, I'm pretty good with this and get 3 parts much more often than 1 parts. Should still make it though, as I have 2 bomb dragons, so usually I can craft 2 of any mining dragon, and even 3 sometimes.