Rear leaf spring shape

[alborz]

Please those who have peterbilt 387 inspect their rear axles and note their air leaf springs.

I'm trying to see if other peterbilt 387s leaf springs are flat or arc shape "between the hanger and where it sits on the top of the axles " on all four springs.
I have grinding noise in my driveline ever since a shop change my bushings. I notice two of my springs are flat and two are arc shaped.
thank you in advance for your help