Kawai BS40 vs BS40 Special

Can anyone out there help me confirm the differences?
All I can find online so far is that the “special” version has Renner hammers. But that’s unconfirmed.

Here are 2 I’ve had in stock before

• Kawai BS40 made in 1988
• And another Kawai BS40 made in 1988

Please email hello@markgoodwinpianos.co.uk with any info you have so I can edit this page

Thanks
Mark