The short answer to your "dual core" question is "yes".
The longer answer is as follows:
Apple added a dual cpu API about the same time they built a dual CPU machine for the first time. The API had some severe restrictions that precluded the second processor from doing any:
1) User Interface displays
2) File system access
3) Function calls that would cause Interrupts
What that left was math calculations. There were a few applications that were updated to take advantage of the API but only a few. Photoshop was one. Final Cut Pro was another.
Both benefitted from the change.