They are supposed to be sending out an email with your share allotment soon. We get the full value amount in 2029 though. Not sure I would call it a "retention bouns" as the value would be based on the market rate on the date of award.
YeArs I was with another coMpany that went publiC and then returned ro private. Didn't even get so much as a thanks for being here when it went public. I still paid my 1% out though. Left before it went back private though.