Call Dominion Equipment Parts, they'll be able to tell you if they will interchange.
Is the track roller for a Morooka MST 600 the same as the MST500 and MST700?
No, if you have an early 600 with eight rollers per side. The 500, 700 and 600V and VD all use the same roller which is somewhat larger than the early 600 track roller. The new 600VD has six rollers per side and is essentially the same undercarriage as the old 500.