Barrel maker ID?

Just bought a large shank 270 WSM varmint barrel off ebay. From the description, I thought it was a factory barrel. But this one doesn't have the factory roll stamping.

The only stamping is right up against the step that some large shank barrels have near the threads. It is stamped D3 and about 180º away has DD in a quarter inch circle.

Does this ring a bell to anyone?

Thanks in advance,
Dana

Never mind, it's a factory barrel that never got installed and roll stamped. My 270 WSM sporter barrel has the circle DD and a D5 stamping.