This article details how to get a list of devices in CAPM that are being managed with SNMPV2 or SNMPV3 in CAPC.
There isn't a way to get the list of devices that are being managed by SNMPV2 or SNMPV3 in CAPC but you can use a rest query to get this information:
Using a REST client, target the DA REST services URL: http://<DA_HOST>:8581/rest/devices/manageable/filtered with a POST request with the following Body:
<FilterSelect xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="filter.xsd">
<Select use="exclude" isa="exclude">
This will get you the list of devices with the ID and name that are being managed with V2 or V3.