Currently 4507 L3 distribution switches are configured for igmp and respective vlan interfaces configured for igmp v3 as shown below.
Then access-layer switches are connected to L3 4507 distribution. Clients (multicast receivers) are then connected to access-layer 3750 24P switches.
Currently I have no multicast configured on switches. Do you see any direct benefit if I explore CGMP on the access-layer switches?
ip muticast-routing distributed
ip multicast multipath
ip multicast rpf interval 1
ip multicast rpf backoff 100 100
ip igmp ssm-map enable
ip igmp ssm-map static list 18.104.22.168
CGMP is legacy your 3750 access switches support IGMP snooping.
The point of attention is that IGMP snooping may be not able to support IGMPv3.
According to the following document IGMP snooping supports IGMPv3 on C3750
For example, if IGMP snooping is enabled on an IGMPv2 switch and the switch receives an IGMPv3 report from a host, the switch can forward the IGMPv3 report to the multicast router.
Hope to help