You're are correct. These switches support IPv4 BGP only. They do support IPv6 but the followinf functions:
IPv6
– IPv6 host
enables switch management in an IPv6 network
– Dual stack (IPv4 and IPv6)
transitions IPv4 to IPv6, supporting connectivity for both protocols
– MLD snooping
forwards IPv6 multicast traffic to the appropriate interface
– IPv6 ACL/QoS
supports ACL and QoS for IPv6 traffic
– IPv6 routing
supports static, RIPng, OSPFv3 routing protocols
– 6in4 tunneling
supports encapsulation of IPv6 traffic in IPv4 packets
– Security
provides RA guard, DHCPv6 protection, dynamic IPv6 lockdown, and ND snooping
Hope you find this helpfull.
Regards, dobias