These are some custom 1911 grips that have been designed as a mold for casting aluminum pieces. As such, the holes are partially filled and undersized for final machining. If you want to install these you will want to modify the hole sizes before printing or drill after fabrication.
04/17/2019 EDIT: NOW WITH HOLES! I've uploaded a model with full through holes so that you can install straight from the print bed.
These are modeled from scratch, using reference dimensions from PrintedFirearm's model https://www.thingiverse.com/thing:610087.
Amazon Basics PLA
I recommend supports if your printer has a moving bed only because of the height. These are setup to print vertically for the best layer resolution.