Well, first of all, there are several different lengths associated with shock measurement. There's the extended length, compressed length, shaft length, body length, travel length, etc...Which length are you talking about?
Also, you have to make sure that the mounting style is the same.
When you searched on the 4WheelParts website, the error returned is that the parts aren't available ONLINE. Call them, and they'll be able to get you a shock that will work for you.
As long as both the Compressed and Extended lengths are close to your factory lengths, and the mounting style is the same, then they'll work. You'll have to consult with a Shock Expert (4WheelParts can help with this) to determine valving, rebound and damping rates of the specific shock you're looking at based on the ride you're after.