The reason for the confusion is that 2007 was the first year of the 2nd gen for the G35 sedans (V36 platform), which got the newer vq35HR motors, BUT 2007 was also the last year for the first gen G35 coupes (V35 platform) which still had the older vq35DE motors.

It's getting better now, but back in '07 it was a real pain sometimes with parts suppliers; they all seemed to assume every G35 was a coupe and it often led to getting incorrect parts if you weren't careful. It's gotten much better now, but occasionally I still find myself telling some confused parts guy that it's an '08 G35 which ends all confusion because the G35 coupes were no longer made then(the coupe had become the G37), so any '08 G35 is a sedan!

Anyway, you're wise to notice the distinction, as nearly all parts are incompatible between the platforms (ie. motor, suspension, brakes, accessories, etc. etc.) If you are ever in doubt or want to verify a part number, check to see if the '08 is listed the same, then you can be a bit more assured.

Congrats on your new ride.