In a bucket with versioning enabled or suspended, the HeadObject operation only obtains the metadata of the current version of an object.

Note If the current version of the target object is a delete marker, the 404 Not Found error is returned. You can specify the versionId to obtain the metadata of a specified version of the target object.
You can run the following code to obtain the metadata of an object: 
package main

import (
  "fmt"
  "os"
  "github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func main() {
  // Creates an OSSClient instance.
  client, err := oss.New("<yourEndpoint>", "<yourAccessKeyId>", "<yourAccessKeySecret>")
  if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
  }

  objectName := "<yourObjectName>"

  // Obtains the bucket.
  bucket, err := client.Bucket("<yourBucketName>")
  if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
  }

  // Obtains a part of the metadata of the specified version of the object.
  props, err := bucket.GetObjectMeta(objectName, oss.VersionId("youObjectVersionId"))
  if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
  }
  fmt.Println("Object Meta:", props)

  // Obtains all metadata of the specified version of the object.
  props, err := bucket.GetObjectDetailedMeta(objectName, oss.VersionId("youObjectVersionId"))
  if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
  }
  fmt.Println("Object Meta:", ret)
}

For more information about obtaining object metadata, see HeadObject and GetObjectMeta.