The lower arm pins are width adjustable, so long as the height is correct (I dont know the height on a 450) to the center link you should be able to. Just make sure the drive line is long enough to stretch out the extra distance.
I bought a 450 tiller in 1993. In 2003 I had to add about 2 inches to the center link of the tiller so that the "A" frame quick hitch would work. I never tried it with the I-Match but I would guess yours will need some work to make it fit.