can I used body.insertFileFromBase64 from Base64String comes from doc file not docx

I have webservice it reads .doc or .docx and send it Base64String by ajax into my plugin this is code of web service

public string ReadDocument(string path)
        {

            FileStream fsStream = null;
            BinaryReader objReader = null;
            try
            {


                ////////////////////////

                // Now, read binary file
                //path = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) + "\\Copy.docx";
                fsStream = new FileStream(path, FileMode.Open, FileAccess.Read);
                byte[] fileContent = new byte[fsStream.Length];
                objReader = new BinaryReader(fsStream);
                objReader.Read(fileContent, 0, fileContent.Length);
                //toRet.FileContent = fileContent;
                //toRet.FileName = "Test.doc";
                string StrBase64 = Convert.ToBase64String(fileContent);
                string _Document = StrBase64 ;
                return _Document;
                // FlushResponse(_Document, "application/pdf");
            }
            catch (Exception ex)
            {
                // FlushResponse("error");
                return "Error " + ex.Message;
            }
            finally
            {
                if (objReader != null) objReader.Close();
                if (fsStream != null) fsStream.Close();
            }
        }

I have a problem with body.insertFileFromBase64 when my Base64String comes from .docx it is working but when Base64String comes from .doc it is not working any this is my code in my plugin I send result param it is Base64String comes from ajax

function InsertDocument(result) {
    Word.run(function (context) {

        // Create a proxy object for the document body.
        var body = context.document.body;
        body.clear();
        // Queue a commmand to insert base64 encoded .docx at the beginning of the content body.
        // You will need to implement getBase64() to pass in a string of a base64 encoded docx file.
        body.insertFileFromBase64(result, Word.InsertLocation.start);

        // Synchronize the document state by executing the queued commands,
        // and return a promise to indicate task completion.
        return context.sync().then(function () {
            console.log('Added base64 encoded text to the beginning of the document body.');
            $("#loading").hide();
        });
    })

Is any Idea to I can insert .doc to office 2016 by office.js or any other function