А ты почитай HELP в самом Word на метод Documents.Open(). У него 3 параметр - это как раз признак, открывать ли документ только на чтение

HELP VBA WordOpen method as it applies to the Documents object.

Opens the specified document and adds it to the Documents collection. Returns a Document object.

expression . Open(FileName, ConfirmConversions, ReadOnly, AddToRecentFiles, PasswordDocument, PasswordTemplate, Revert, WritePasswordDocument, WritePasswordTemplate, Format, Encoding, Visible, OpenConflictDocument, OpenAndRepair , DocumentDirection, NoEncodingDialog)

expression Required. An expression that returns a Documents object.

FileName Required Variant . The name of the document (paths are accepted).

ConfirmConversions Optional Variant . True to display the Convert File dialog box if the file isn't in Microsoft Word format.

ReadOnly Optional Variant . True to open the document as read-only. Note This argument doesn't override the read-only recommended setting on a saved document. For example, if a document has been saved with read-only recommended turned on, setting the ReadOnly argument to False will not cause the file to be opened as read/write.

AddToRecentFiles Optional Variant . True to add the file name to the list of recently used files at the bottom of the File menu.

PasswordDocument Optional Variant . The password for opening the document.

PasswordTemplate Optional Variant . The password for opening the template.

Revert Optional Variant . Controls what happens if FileName is the name of an open document. True to discard any unsaved changes to the open document and reopen the file. False to activate the open document.

WritePasswordDocument Optional Variant . The password for saving changes to the document.

WritePasswordTemplate Optional Variant . The password for saving changes to the template.

Format Optional Variant . The file converter to be used to open the document. Can be one of the following WdOpenFormat constants.

WdOpenFormat can be one of these WdOpenFormat constants.
wdOpenFormatAllWord
wdOpenFormatAuto The default value.
wdOpenFormatDocument
wdOpenFormatEncodedText
wdOpenFormatRTF
wdOpenFormatTemplate
wdOpenFormatText
wdOpenFormatUnicodeText
wdOpenFormatWebPages

To specify an external file format, apply the OpenFormat property to a FileConverter object to determine the value to use with this argument.

Encoding Optional Variant . The document encoding (code page or character set) to be used by Microsoft Word when you view the saved document. Can be any valid MsoEncoding constant. For the list of valid MsoEncoding constants, see the Object Browser in the Visual Basic Editor. The default value is the system code page.

Visible Optional Variant . True if the document is opened in a visible window. The default value is True .

OpenConflictDocument Optional Variant . Specifies whether to open the conflict file for a document with an offline conflict.

OpenAndRepair Optional Variant . True to repair the document to prevent document corruption.

DocumentDirection Optional WdDocumentDirection . Indicates the horizontal flow of text in a document.

WdDocumentDirection can be one of these WdDocumentDirection constants.
wdLeftToRight default
wdRightToLeft

NoEncodingDialog Optional Variant . True to skip displaying the Encoding dialog box that Word displays if the text encoding cannot be recognized. The default value is False .

Может имеет смысл вместо отдельного приложения Word разместить внутри стандартной формы компонент Ole?

Как это сделать посмотри стандартный проект примеров


Форма OleWord.scx