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Most (all?) Cisco switch have some sort of default QoS policy when it's enabled. The default often is very, very basic. Whether such a default is suitable for you would you require comparing what's it doing to your needs.
Also, later Cisco switches have some sort of AutoQoS command that provides a common or best practice implementation QoS policy. This too, if supported and enabled, should be compared to your needs.
For example, when you enable just QoS you might go from one output queue to multiple queues on an egress port, but each with some simple bandwidth sharing. AutoQoS might enable one queue as a priority queue and "tweak" queue bandwidth allocations, drop policies and how frames/packets are directed to the queues.
All of the above is a long way of say, probably not, to "But this is it?". However, you also may not need to define policy maps and class maps, etc.
