I am building up a 2012 5.7 frame and was wondering if the front deraileur is screwed down in the 2 holes right to the frame or if there are any spacers or grommets that fit behind. I have the Shimano XT m770E and there was a little nylon spacer included in the plasic bag. I didn't want to put everything together and find out I have shifting issues and wondering about the proper placement. Thanks for the help.