There are two model MacBook Pro (retina 13-inch and 15-inch Mid-2014)
The 15-inch Mid-2014 specs according to http://mactracker.ca database app shows as Quad-Core i7:
The 13-inch MacBook Pro specs (confirm same source) is only Dual -Core:
The 15-inch MacBook Pro retina (15-inch, Mid 2015) also shows a quad-core i7 processor.
Older 15-inch MacBook Pro (2013 also shows i7 quad & 4-core processor.
Another source to compare specs, is http://everymac.com for most Apple product specs.
{PS: some fringe model specs may have offered an i7 4-core as an upgrade option,
shipped direct from Apple online; IF so the base-trim model, may show i5 2-core.}
Good luck & happy computing! 🙂