Hello,   Correct. Drives do not have to share a common part number for compatibility, but you would want to uniformity among the type of drives in each array. The part numbers you listed are both 400GB SSDs and both were validated for use with the platform.
Does Powervault MD3620 support having drives of the same type but different DP/N Number inside the same raid setup? I consider buying used MD3620 and add DELL SXKLTK SSD 400GB drives and install in the same raid, and they come with different DP/N Number: example:  T2TPF and C06VX
Powervault MD3620 and support of drives of same type but different DP/N Number 
in same raid