The Gold Dot is totally a jacketed bullet!
I've loaded gold dots in 357mag,45acp,45colt,44mag and they have all had jackets
It's still a jacket, but it's plated on the lead core - instead of being drawn from sheet copper.
Speer is unlikely to give you any data for magnum loads with the 200 gr GDHP. It's too soft, and risks forcing cone damage at magnum velocities/pressures. (And those velocities are beyond its designed expansion window.)
But, if you want to take the risk yourself...
Their 200 gr .44 Mag JHP (tougher than the GDHP) lists the following:
26.5-28.5 gr H110 / 1590-1688 fps (7.5" Redhawk)