69 Chevelle guys have a Elcam question on brakes

[Zman1969]

I just picked up a 69 Elcamino project engine was pulled and it sat since 1981 the booster, master and calipers had been pulled and I got the parts that were removed the booster is the issue it is a factory PDB car and the booster that came with it is 9354 dated 063 but it's not 9391 as I expected anyone chime in on this? it was produced 03B

thanks I guess it really doesn't matter since its not a SS car but I'd like to keep it original anyway