The information was in the document they sent me, they should’ve removed it completely if they didn’t want me to see it. The situation is identical to them mailing me a paper copy with a black piece of paper scotch taped over the price.
There are zero legal implications, it was a private contract. My customers regularly tell me the exact price that my competitors have submitted to them and that isn’t illegal.
Probably there are legal implications for attorneys circumventing redaction in legal documents but construction proposal letters have no protections against unredaction.