1995 Cobra valve covers

I just got a set about an hour ago. I have heard that theMN-12 Thunderbirds share the same covers but without the "COBRA" letters. I have a set of both (MN-12 Thunderbird covers, steel crate motor covers, and the Cobras), and they are not the same. The Crate motor and T-Bird covers seem the same, other than color. BUT, the Cobra valve covers seem heavier, and solid as a rock. What is the difference with them?

I always thought the cobra covers were the same as the explorer/mountaineer.

nvm google says I was wrong.

I think they may be visually similar, but there's some kind of difference.

cobras apparently have the word cobra stamped into them. otherwise they appear to be the same casting. At least as far as I can tell.

Side by side they even seem different. As if the Cobra cover is thicker, or possibly (maybe I'm thinking too much) double walled?

thats odd.