Yes, the newer MIB is described as a clarification. Here's an except from the comments. The revision entry agrees with the last updated entry.

<     REVISION      "200006140000Z"
<     DESCRIPTION
<             "Clarifications agreed upon by the Interfaces MIB WG, and
<             published as RFC 2863."

        There appear to be some general changes, consolidation, etc., at various places in the MIB.
Chris Six,  PJM