Can we clone an object from any external Salesforce org (org in which BOFC is not installed)?

Yes, BOFC has a capability to clone an object from same org or any external non-linked org

Experience it for yourself

Bulk Object Field Creator (BOFC) is a must-have tool, designed specifically for Administrators, that simplifies many of the tedious tasks of managing a complex Salesforce environment.

This tool is available on Appexchange and Click on below button to install the
latest version of BOFC

or learn more