RB-250 tonearm installation Systemdek iix

I am replacing the Profile tonearm on a Systemdek iix with a Rega RB-250. The RB-250 came with RCA connectors, the arm I removed had RCA connectors and a ground wire. Since the RB-250 does not have the external ground wire that the Profile arm had I'm guessing it does not need it. I have googled what I thought I was looking for and did not find any help. The TT has a ground from the chassis/board/lower panel to a stud on the back that has the lead to hook to my pre-amp but the tonearm itself does not have a lead. Any guidance would be greatly appreciated.
my one experience with a RB250 was it played fine without a ground wire, but if you have a ground wire attached to the sub-chassis of the table you can try to connect it to your preamp ground. If you hear hum, I would disconnect it and see how it does. If you still have hum you may need to fix a ground wire to the base of the arm somehow (the easiest way would be a wire with an alligator clip).

Separate question - forgive my asking if you already know this - the Rega arm has different geometry than the profile. Did you get a correct arm board for it?
IIRC, the RB250 combines the arm ground wire to the left channel ground at the rubber block in the base of the arm.
Bdgregory: I made a few new arm boards and used the rega template to locate the mounting hole in one. Unfortunately when mounting the cartridge the white wire came loose which is actually a good thing because I'm sure it's condition would have caused problems. I now have a cardas kit on order ;-)
The JA Mitchell mod, the counterweight, for that arm, is the best. It puts that arm in another league. You definitely should try it.