Could just as easily be A4, just because you see 'workers' with 250-280 mh/s that doesn't prove anything.
Using the Nicehash chart, they've been averaging 251Mh per miner (40728/162) for the last 1.5 hours. That's pretty close to the L3 specification of 250MH which would incline one to believe these are L3s given the A4 instability issues.