This is a modern Army Good Conduct Medal. It was first issued in 1941 but is still issued today and this one is a recently made set. Any Active Duty Army soldier who serves honorably for 3 years receives one. Making it one of the most common medals for the Army. This is a standard presentation set that wouldn't be older than the late 80s by the backing it's on. You can pick them up GSA or any military clothing without proof of reciept. Still they are about $15 to $20 for this full set and it looks like it hasn't been taken off the card.
The WWII era version of this medal came in a dark blue box with a Dark blue felt like coated card stock. Also the WWII time frame version has a shorter ribbon on the medal. The backing for the Vietnam era release has a white card stock backing like this but they had a "V" cut out to hold the medallion of the metal in place in the packing and they came on a cardboard box. Again this would be from the 80s at the latest based on the card stock. Recent medals come on an white backing also but most of the manufacturers mount the ribbon bellow the medal on the card backing so it's obviously not a recent issue.
As far as the actual backing of the medal and ribbons. That hasn't changed since WWII. Don't fix what isn't broken.
Do you have any more medals that came in that sale? I collect vintage medals. Usually older ones but I'm also looking for some for a friend that's looking to replace his lost medals from his service mid 80s to early 90s and I'm sure he'd rather have period made medals rather than bright shinny new ones.