diff --git a/rest/client.go b/rest/client.go
index 393a4166..159caa13 100644
--- a/rest/client.go
+++ b/rest/client.go
@@ -238,7 +238,8 @@ func (c *RESTClient) Delete() *Request {
 
 // APIVersion returns the APIVersion this RESTClient is expected to use.
 func (c *RESTClient) APIVersion() schema.GroupVersion {
-	return c.content.GetClientContentConfig().GroupVersion
+	config, _ := c.content.GetClientContentConfig()
+	return config.GroupVersion
 }
 
 // requestClientContentConfigProvider observes HTTP 415 (Unsupported Media Type) responses to detect
@@ -257,25 +258,35 @@ type requestClientContentConfigProvider struct {
 }
 
 // GetClientContentConfig returns the ClientContentConfig that should be used for new requests by
-// this client.
-func (p *requestClientContentConfigProvider) GetClientContentConfig() ClientContentConfig {
+// this client and true if the request ContentType was selected by default.
+func (p *requestClientContentConfigProvider) GetClientContentConfig() (ClientContentConfig, bool) {
+	config := p.base
+
+	defaulted := config.ContentType == ""
+	if defaulted {
+		config.ContentType = "application/json"
+	}
+
 	if !clientfeatures.FeatureGates().Enabled(clientfeatures.ClientsAllowCBOR) {
-		return p.base
+		return config, defaulted
+	}
+
+	if defaulted && clientfeatures.FeatureGates().Enabled(clientfeatures.ClientsPreferCBOR) {
+		config.ContentType = "application/cbor"
 	}
 
 	if sawUnsupportedMediaTypeForCBOR := p.sawUnsupportedMediaTypeForCBOR.Load(); !sawUnsupportedMediaTypeForCBOR {
-		return p.base
+		return config, defaulted
 	}
 
-	if mediaType, _, _ := mime.ParseMediaType(p.base.ContentType); mediaType != runtime.ContentTypeCBOR {
-		return p.base
+	if mediaType, _, _ := mime.ParseMediaType(config.ContentType); mediaType != runtime.ContentTypeCBOR {
+		return config, defaulted
 	}
 
-	config := p.base
-	// The default ClientContentConfig sets ContentType to CBOR and the client has previously
-	// received an HTTP 415 in response to a CBOR request. Override ContentType to JSON.
+	// The effective ContentType is CBOR and the client has previously received an HTTP 415 in
+	// response to a CBOR request. Override ContentType to JSON.
 	config.ContentType = runtime.ContentTypeJSON
-	return config
+	return config, defaulted
 }
 
 // UnsupportedMediaType reports that the server has responded to a request with HTTP 415 Unsupported
diff --git a/rest/request.go b/rest/request.go
index 65942aa1..0ec90ad1 100644
--- a/rest/request.go
+++ b/rest/request.go
@@ -156,14 +156,10 @@ func NewRequest(c *RESTClient) *Request {
 		timeout = c.Client.Timeout
 	}
 
-	contentConfig := c.content.GetClientContentConfig()
-	contentTypeNotSet := len(contentConfig.ContentType) == 0
-	if contentTypeNotSet {
-		contentConfig.ContentType = "application/json"
-		if clientfeatures.FeatureGates().Enabled(clientfeatures.ClientsAllowCBOR) && clientfeatures.FeatureGates().Enabled(clientfeatures.ClientsPreferCBOR) {
-			contentConfig.ContentType = "application/cbor"
-		}
-	}
+	// A request needs to know whether the content type was explicitly configured or selected by
+	// default in order to support the per-request Protobuf override used by clients generated
+	// with --prefers-protobuf.
+	contentConfig, contentTypeDefaulted := c.content.GetClientContentConfig()
 
 	r := &Request{
 		c:              c,
@@ -176,7 +172,7 @@ func NewRequest(c *RESTClient) *Request {
 		warningHandler: c.warningHandler,
 
 		contentConfig:     contentConfig,
-		contentTypeNotSet: contentTypeNotSet,
+		contentTypeNotSet: contentTypeDefaulted,
 	}
 
 	r.setAcceptHeader()