Yes. An E8400 was on the cusp of the DDR2/DDR3 mainstream switchover. Boards exist that support the E8400 + DDR2, as do boards supporting E8400 + DDR3.
I believe there's even a couple of boards with X number of DDR2 slots and Y number of DDR3 slots..... although you can only use one or the other.
tl;dr Yes.