I bought two of these motors and two 30 RPM motors, all at the same time.
Both of the 30 RPM units produce higher torque than the 5 RPM units.
One 5 RPM stalls at about 110mA. The other stalls at about 1A. Of course the one that stalls at 1A produces much greater torque, though I have no instruments for measuring it. The actual motor bodies have different markings - one has a stick-on paper label, the other has etched or laser-engraved markings.
Unfortunately, until you have these motors in your hands, you may not know what you are getting.
(I tried the 30RPM for my application, and found the torque was not quite enough. Oh, sez I, the 5RPM should produce more than enough torque! No such luck. I'm going to try running at 18V.)