Both controllers are based on LSI 1030 chipset and there will be 100% HW compatibility. Metadata is stored across the members of the array. You will need to activate RAID volumes from controller BIOS during bootup. Controller won't erase anything unless you want to do that or you set it up so, but anyway, there is no 100% guarantee for data loss prevention. I'm sure disks are low-capacity disks, so it's easy to backup them if you can get couple hours for maintenance window.
Will it boot OS? Some guys are reporting problems booting Windows after this procedure.
What are reported problems? Disks must be very old already, and failing... Got SMART status?
Also, there are Adaptec-based ServeRAID-6i controllers (CARDS). This one is incompatible with LSI metadata format.