Just to add a data point in case someone is searching for an answer to this question, like I was a few months back:
I was booked earlier this month on an AA operated flight with a BA flight number from LHR to LAX, in premium economy. I confirmed with AS that this would earn me miles, prior to purchasing, since this was the flight that pushed me to MVPG. Originally the credit did not post (I also flew ARN-LHR on the same ticket, but on BA metal, which posted a week later). I submitted mileage request online and was denied. Called Mileage Plan and gave details, was told to email my ticket receipt and boarding pass to Mileage Plan. Flights were credited a few days later.
TL;DR: Codeshare flights still credit if the operating flight is within the range.