IGN posted a little earlier in the week that Halo: CE and Halo 2 Classic are getting their own set of medals for campaign and multiplayer in the Master Chief Collection. 343 told IGN there would be more information in the next Halo Bulletin but said,
We felt this addition would make the multiplayer experience feel more modern and give players more ways to track their progress and style.
Halo fans who want a more original feel to their games, medals can be turned off and for Halo 2 can be toggled to the classic medals used in the original release. Campaign medals have also been added an awarded for enemy and style kills. The new campaign medals are part of the new unified campaign scoring system, which varies slightly from it’s Halo 3, ODST and Reach counterparts.
Since the post was made, the latest Halo Bulletin has been posted and details about a new Medal Chest has been revealed. The Medal Chest is one of the new career screens that shows up under the unified UI where you will track your stats and accomplishments in multiplayer and campaign. If you’ve decided you want to go the classic route and not have medals shown for Halo 1 or 2, you still get them in the background and will show up in the post game report and your career stats. New medals will be added to Halo 2 Anniversary’s new supported gametypes along with a tier of more serious medals called Legendary medals. These medals include accomplishments like Extermination, Perfection, Steaktacular, Killionaire, and Triple Double.