Was surprised to hear someone mention this was healing for 90 and getting hit by the non-cleric healing penalty. The singing steel definitely healed for 100. Here's some evidence.
https://web.archive.org/web/20001102...ML/000243.html
https://web.archive.org/web/20010501...ID=1774&page=2
This eqdiva archive from 2001 is only recorded in the preview mode but you can still see the amount and the date.
https://search.eqarchives.org/search...asp_id%3D10%22
These sources span from early 2000 to late 2001, which both pre-dates and extends beyond the time frame as the sources referenced in
the old post that had
all other breastplates reduced to 90, which confirms that it always was 100 for bards.
Bards were on their own very unique spellcasting system, which is why their items also could be used while meleeing, moving, etc.
They were exempt from the 10% penalty because it would have affected their healing line of songs.
So this one should not have been affected by the changes.