Not a clear answer, but a possible alternative.
1st, connect all three intact as they are now to the new system. Confirm the array functions as it did before.
Shuck and install 1 drive, parity would probably be best for testing, and do a non-correcting parity check. If zero errors, you should be ok to shuck the other 2. If you get a bunch of errors, stop and build parity from scratch, then after you get a clean non correcting check you should be good to go to shuck 1 more, and rebuild it, do a non-correcting check, repeat for the last drive.
Make no mistake, your data is at risk here, so if any of what I'm saying is unclear, ask questions. You really need to understand the why and the how of each step so you don't make an error that erases your data.
Ideally, you should purchase 2 more drives, and use those in the array and leave your current data drives intact as backups. That way there is much less pressure and you have a good foundation of backups to build on.