Answer
Yes, Junos OS supports the standard MIB ipNetToMediaTable, which is described in RFC 2011, SNMPv2 Management Information Base for the Internet Protocol using SMIv2.
This table is used for mapping IP addresses to their corresponding MAC addresses. Both IP and MAC addresses display in the same table.
For a list of supported standard and enterprise-specific MIBs, click SNMP MIBs and Traps Reference