inland surfer blue lake... changes over the years?

Is there any big difference between an "original" blue lake and today's 2 fin model? I know I can get a quad and a carbon railed quad, but is a 2 fin a 2 fin?

The quad gives you the option of running 4 fins but will come with only 2. The older model will still work for ya just fine. I have the quad and run just 2, however, I picked up a set of "big boy" fins from Inland and they're awesome. All my buddies are getting them for their bluelakes/red woody's. I've ran 4 fins once and it made the board trac straighter but not near as mobile

The Quad and Carbon Rail Blue Lake are the same boards in the way of shape. Over the years we have updated the rails making it a faster board from the very first original Blue Lake we introduced. Some riders like just two fins which make it looser and some like the drive 4 fins give you for air. The big Boy Fins are a great in between as Matt has mentioned.

so what are the pros and cons b/w the carbon rail and the non? Is there a big difference?

Carbon is very durable + adds some stiffness + looks cool. We will be using carbon rails on the Keenan 4-Skim and the Fly Boy this seaon also.
cheers, jf