I believe you have a couple of recalled adapters there. The 10-30 & 14-30 with the black back where pre-recall and the light gray backed 10-30 is one of the post-recalled adapters.
"How to determine if your adapter is affected by the recall
Your adapter will likely be included in the recall if you purchased it more than six months ago. To check, compare the part number on the prong side of the adapter to the table below. If you find a match, your adapter will be replaced.
Recalled Adapter Part Number
NEMA 6-50 1016021-00-A
NEMA 6-50 1016021-00-B
NEMA 10-30 1016174-00-B
NEMA 14-30 1018243-00-A
NEMA 14-30 1018243-00-B
The latest version of the NEMA 14-30 adapter does not need to be replaced. They have part number 1018243-00-C and have a gray plastic cap (on the right in the photo), rather than a black plastic cap (on the left in the photo)."