Going nuts about these nuts - part ID help needed

[Dakota]

I've been slowly eliminating my parts piles.  I have a box of small stuff that I purchased months or years ago, most of which I've re-remembered what they were for except for the flanged nuts on the left in the picture below.  What would these be used for?  Thread size is about 1/4".  Flange is 1" across. The nut on the right, included for reference, is for attaching the seats to the car.

Most of the small parts I've purchased arrive with some kind of tag or marking that helps me figure where it goes.   These nuts were apparently shipped in an unmarked baggie. 

[js27]

Kind of look like the nuts that hold the heater box to the firewall or the ones that hold the seats down but they have a serrated edge on them I believe.
JS27

[anlauto]

No...those nuts are used on the battery hold down. I doubt you'll find them anywhere else on a 1970 E Body.

[Dakota]

No...those nuts are used on the battery hold down. I doubt you'll find them anywhere else on a 1970 E Body.

Yes!    Thanks Alan.  The pic is probably small, but the photo below from Rosevill's website shows all the pieces of the battery hold down (including the nuts).