wiper bottle mounted on core support?

[wreckedchevy]

i'm chopping up a front clip for a secret project i'm working on and I noticed the wiper bottle is mounted to the core support? I've never seen this before is it common? certain year only thing? the donor I believe is a 69 last registered in 81 my folks bought it for $50 in the 80's to turn into a trailer I rebuilt and grenaded the original 307 in my stepside 18 years ago. the pics are below



http://s1054.photobucket.com/user/wr...?sort=3&page=1