thanks, I found the reference
the CRI change depending which filter, is up to 3 points change in CRI Ra, and up to 10 points change in CRI R9
imo no, I do not think the CRI improvement to a Low CRI LED, is significant at all.
these are minus green filters:
they replace green tint with pink tint, at the cost of lumens
but they wont change a Low CRI LED into a High CRI LED