From a DNS point of view yes. DNS works on IP level, so for Pi-hole they are unique clients. From a human point of view it might be the same client. But having Pi-hole to judge what constitutes as a single client is nearly impossible. Different users will have different opinions about this, sometimes definition will change according to the problem to solve: Client defined by IP, hostname, MAC, interface, physical device...?
You might want to check out Alias clients, see the thread here