From Imagination Technologies' The MIPS32® Instruction Set v5.03
with emphasis added for clarity (registration required for download of the whole document)
Format: JALR rs (rd = 31 implied)
JALR rd, rs
Restrictions:
Register specifiers rs and rd must not be equal, because such an instruction does not have the same effect when reexecuted. The result of executing such an instruction is UNPREDICTABLE. This restriction permits an exception handler to resume execution by re-executing the branch when an exception occurs in the branch delay slot. ))
In other words, they're strangely enough both correct.