If I got an electric guitar, would I know how to play acoustic after learning that?

Sorry Tony B, but you are quite simply wrong. "you never see or hear a guitarist play one type and then change to another type" I have Ovation VXT, which has both acoustic and electric pickups, can play as both. The fretboards, tunings, etc are the same between electric and acoustic. I learned on electric, got acoustic later. The main difference is acoustics generally take more finger pressure. Saying as different as violin and trumpet has no basis in fact. First electric guitars were simply acoustic guitars with pickup mounted on them (and many still do that). In this video around minute mark these guys talk about the two types of sound in VXT. http://youtu.be/IM0bpbMknF8

And a short vid of Michael Kelly hybrid. Has standard acoustic bridge/saddle with FIshman under saddle pickup along with humbuckers. http://youtu.be/DsXPIq7kHyM

They are tuned and played pretty much exactly the same. Specific techniques will differ between them, but those techniques are far more advanced than you'll be learning for several years (at minimum).

Acoustic guitars are a little harder on your fingers, but tend to be cheaper because you don't need to buy an amp as well.

If you can play one, you can play the other.

They are COMPLETELY different things. That'why they're both called guitars and that's why you never see or hear a guitarist play one type and then change to another type - because the two types are as different as violin and trumpet!