trying,
I believe you've posted the casting number, (not the part number)
which which happens to be the same for the front and rear.
5451615 is the Chevrolet part number for the rear.
5450071 is the Chevrolet part number for the front.
The difference probably being in the adjusters.
I don't think the original part numbers would be of much use now unless you were verifying NOS parts.
