I know from your smiley face that you're kidding, but there may be some substantial differences for the 1300 to weigh 10 lbs more than the 500.
Maybe Denon is taking the true audiophile path and differentiating the turntable on price alone.
:-)
In English, here are the specs for the DP 500M at Needledoctor: http://www.needledoctor.com/Denon-DP-500M-Turntable?sc=2&category=348
And here are the specs for the DP-1300mkII at AudioCubes II: http://www.audiocubes2.com/category/Turntables/product/Denon_DP-1300MKII_Analog_Turntable.html
As you can see, the 1300's arm is 14mm (.6") longer and the turntable's overall weight is 4.5KG (9.9 lbs) heavier. I'm hoping that the arm is a newer design to accommodate today's cartridges. It definitely uses a different counterweight. The extra length should reduce tracking angle a bit. If you look closely at the pictures of the two, the arm base on the 1300 is further away from the platter.
It also appears that the 1300 has a nicer wood veneer finish with a more prominent grain and chamfered edges and corners.