Actually not directly. You can think of it like this:
The Classic II was based on the 68030-based LC II that was designed to fit in a Classic case.
The SE/30 was based on the 68030-based IIx (actually more like the IIcx) that was designed to fit in a SE case.
The LC II was a 68030-based upgrade to the 68020-based LC (that was actually released after the Classic II, but all LC II added besides 68030 that was not in Classic II was 4 MB soldered RAM because by then Apple finally realised 2 MB was not enough for System 7).
The IIx similarly was a 68030-based upgrade to the original 68020-based II.