No, there is currently no dedicated private API endpoint (behind basic auth or token) that exposes the product version separately.
i think It was removed mainly for security reasons.
IF we do Exposing productVersion publicly allowed:
- Easy version fingerprinting
- Automated CVE matching
- Targeted attacks against outdated instances
Since the version is not required for WOPI functionality, it was considered unnecessary metadata and removed to reduce information leakage and attack surface.