They are only 4 years apart, so both are "modern" and multi-coated. Optically there shouldn't be any difference, in theory at least.
But the LTM version introduces a variance - the M adapter, of which not all are created equal. You may get focus issues if the lens, the adapter and the M camera (more so if it's digital) are not paired well.
Also notice you can can buy the PII version new, which means warranty and factory-spec adjustment, for not much more.