Can I use the same harness/computer from one LSx with another engine?

[joeydurango]

Okay, a bit of a story here. Got the LS swap running. Love it, does everything I'd hoped. Only problem is that there's a bad knock in our used engine. That sucks, of course. Trying to work it out with the vendor, but so far no dice, they're being difficult. More on this later after we resolve it one way or another. In any case, we're way too far into this truck to stop now, which leads me to...

My question of the day: If I were to just say screw it and purchase a new/remanufactured long block, is it as simple as buying a 5.3 LS-based engine and swapping it out? We have a custom harness, we have a computer dialed for the harness, we have all the accessory drives, manifolds, etc. from the current engine. The current engine is nothing fancy, no performance tune or anything, out of a 2002 Silverado. I'm not savvy enough to know if there's something specific about a given long block that makes it different from any other 5.3. I see here that Summit has a 5.3 GM long block, and that they specify it's for '99 GM trucks with a VIN beginning with LM7, but I have no idea why it's so specific, especially since it isn't as if they have an entire lineup of years/VIN prefixes to select from. Anyone care to educate me on this? Thanks!