I have a Racemaster holster. I assume the Racer and the Racemaster are similar in the way they hold on to the trigger guard.
I have tried a few different 2011 type grips with my holster. My experience is that if the trigger guard is undercut, even double undercut, and the front of the trigger guard in unmodified, no problem. I purchased an older SVI pistol with polymer grip 2011 polymer gip pistol with a trigger guard that had been rounded. The front was no longer flat. When the holster was locked, the gun sat in the trigger guard block of the holster securely but could rock (tilt) pretty far forward. When the holster was not locked the gun sat in the holster well enough to start a stage, draw re-holster and then re-lock. Short term acceptable for me, but way less than ideal. I went looking for a new SVI polymer grip immediately and was relieved when I changed it out.
Assuming again that the locking mechanisms for the Racemaster and the Racer holsters are the same or similar, if you have 2011 grips where the front of the trigger guard has been rounded or modified, I don't think you will be happy with that set up. I hope this helps.