It's too little for me to go on. Check back if you get more information.

BTW, they didn't use aluminum for IC packaging. You're probably referring to a ceramic package.
View attachment 254111View attachment 254112
EDIT:
They do use aluminum packages (e.g. TO-3), but not for DIP packages.

 

View attachment 254119

That certainly looks metallic, but I think they'd choose materials that had similar contraction/expansion properties so the hermetic seal wouldn't be damaged from temperature cycling.

TI (National Semiconductor) only discuss 3 package types with hermetic seals: ceramic with a lid that's soldered on, ceramic top and bottom, and metal cans.

 

That certainly looks metallic, but I think they'd choose materials that had similar contraction/expansion properties so the hermetic seal wouldn't be damaged from temperature cycling.

TI (National Semiconductor) only discuss 3 package types with hermetic seals: ceramic with a lid that's soldered on, ceramic top and bottom, and metal cans.
View attachment 254120

Yes, its actually a sandwich with what looks like aluminium top and bottom and white ceramic in-between - I've not seen this before

 

I wonder if it could be low-alpha lead shielding?

 

Looking for sheet or info on Texas Instruments CMP1312; specifically the voltage/current specs. I am told it is the same as a TMS-1100 but can find no documentation thereof.

Any help appreciated. I wish I had found this thread years ago. Great stuff!
Cheers
Dukester