Which WIM file to update for a SCCM boot image?

Recently, I created a boot image using the SCCM admin console but forgot to add some necessary files to it. Rather than delete the boot image and start over, I decided to use DISM to mount the WIM file and add what I needed. When I looked at the package source for the boot image, there were two WIM files. One was WinPE.Wim and the other was WinPE.<>.wim. I decided to update the WinPE.wim. I mounted it and added the needed files. Once completed, I updated the distribution points and tested it. The files I added with DISM were now available in my boot image.

Which WIM file to update - Pic1.JPG