Those will fit fine. 5X7 = 6X8, they use the same hole pattern.
However, I would NOT buy them from Crutchfield. I know they are popular, but they are also seriously overpriced.
Same speakers, but $30 cheaper.... Amazon.com: Pioneer TS-A6874R A-Series 6"x8" 3-Way 350 Watts: Car Electronics
And if you want a big Crutchfield type retailer but still want the savings, try SonicElectronix. Pioneer TS-A6874R (TSA6874R) 6" x 8" 3-Way A-Series Speakers