I haven't been able to confirm anything either way.
I have seen reports citing "unidentified sources" from both the USN and USMC saying that the ex-RAF Harriers "are for parts only and will never fly" and others saying "2 squadrons will be transitioned to Harrier GR.9As"... also from both the USN and USMC, and also refusing to be named. More have used the vague "no current plans to fly them" evasion.
Both the USN and the USMC have yet to officially say anything either way... they have been asked by the news media, but would not comment.
I suspect that they are taking a hard look at what it would take (and cost) to bring a squadron or two's worth of GR.9As into service, and are comparing that to the cost of keeping the F/A-18s operating (and for how long they can be continued).
I believe the final decision will combine those assessments as well as any further IOC slippages of F-35B.
So we can't say for sure yet yes or no.