First, take some of the stuff on Vintage Knob with a grain of salt; that site is not always perfectly accurate.
Second, if you can find the IC as an NOS part, via Alibaba or other internet source, it will probably cost a few bucks each. And you would be MUCH better off at a MUCH lower cost than trying to source the IC by buying a whole turntable. You would have to pay the cost for a working unit, too.
As to platter mass, the SP10 Mk3 has the heaviest platter that I know about among Japanese vintage DD turntables, except possibly for the optional and very rare gunmetal platter for the Yamaha GT2000X. But that latter platter will cost you about as much as a good GT2000, if you can ever find one. (For the heck of it, I have been searching.) The L07D platter is substantial but only a fraction of the weight of the other two. It can be enhanced by the addition of an optional peripheral ring specifically made by Kenwood for the L07D, which I own but don't use. The SP10 Mk2 platter is not much different in weight from that of the TT101 and the Denon DP80. I don't know about the Luxman platter; there are a few owners on this thread who may tell us. One determinant of platter mass back then may have been the choice of motor. For a given physical size, coreless motors produce less torque than do iron core motors, but the correlation between coreless motors and platter mass is not linear, either, except to note that the Mk3 uses a gigantic iron core multi-pole motor. The Pioneer Exclusive P3 has an impressive platter and uses a coreless motor, on the other hand. The GT2000 uses a coreless motor but had an optional oversize bearing and that optional massive platter to be driven by that same coreless motor.
Second, if you can find the IC as an NOS part, via Alibaba or other internet source, it will probably cost a few bucks each. And you would be MUCH better off at a MUCH lower cost than trying to source the IC by buying a whole turntable. You would have to pay the cost for a working unit, too.
As to platter mass, the SP10 Mk3 has the heaviest platter that I know about among Japanese vintage DD turntables, except possibly for the optional and very rare gunmetal platter for the Yamaha GT2000X. But that latter platter will cost you about as much as a good GT2000, if you can ever find one. (For the heck of it, I have been searching.) The L07D platter is substantial but only a fraction of the weight of the other two. It can be enhanced by the addition of an optional peripheral ring specifically made by Kenwood for the L07D, which I own but don't use. The SP10 Mk2 platter is not much different in weight from that of the TT101 and the Denon DP80. I don't know about the Luxman platter; there are a few owners on this thread who may tell us. One determinant of platter mass back then may have been the choice of motor. For a given physical size, coreless motors produce less torque than do iron core motors, but the correlation between coreless motors and platter mass is not linear, either, except to note that the Mk3 uses a gigantic iron core multi-pole motor. The Pioneer Exclusive P3 has an impressive platter and uses a coreless motor, on the other hand. The GT2000 uses a coreless motor but had an optional oversize bearing and that optional massive platter to be driven by that same coreless motor.