Stock color for 57 T bird chassis ?

I'm sending the frame and suspension for blast and paint next week. I'm sure some of you guys know the correct chassis color for a 57 ? Thanks!

 

I did my Pops 57 in black imron about 20 years ago.

 

i just got a 56 in shop this weekend. chassis's already done in black. came with a million page restoration manual so i assume he didn't stray from plan there.