70 challenger, what are A13, and H6K4 codes?

[upnover]

I am looking at a project for my wife, pretty basic 70 challenger, 318/904 auto, wht vinyl top, burnt orange paint, base radio, bucket seats, etc. what I am not sure of are the A13 code, my govier book shows its the 440 upgrade on a 69 cuda and the superbird pkg on a roadrunner in 70. im gonna guess its spring special? the other one is H6K4, cant find that one any help would be appreciated     

[1 Wild R/T]

Where is the A13 located? second row from the bottom & second group from the right? If so it's the SPD which would be Oct 13..

H6K4 is vinyl Bucket seats in burnt orange..

[upnover]

yes it is the second row, and second one in from right, so im sure you are right about the build date, thanks you. and thanks on the other code, the car is mostly a shell but it has burnt orange rear door panels so i figured it was all burnt orange. thanks again, i appreciate it.