I would agree with you Lynn on the rear.
My 04C Z10 had a 0413 dated rear according to the POP.
The rear is still a good code BT = 3.55 posi.
I think the trans code is missing the last letter (A,B, or C) also??
My car has an HB engine code for the 350/300 auto.
I think the HA code is correct for the 4spd cars.
Also the 041 heads would be the right castings.
Is the block a 386 or a 388 casting?
Mine is a 388.
I'll get the build date off of my block tonight to see how close it is the the car build date.
Eric