Not necessarily.
An 020 is about as fast as an 030 at the same clock speed. (Not like the difference between the 030 and 040 at the same clock).
You are probably right. 030 has 256bytes of memory for both data and instruction caches (68020 only has instruction cache IIRC)*and supports burst modes (useful for c2p). Motorola used 020,040,060 for major revisions and 68010,030 were minor ones.
