A/c heater question

[revjames]

So I have a 1962 c10 for a parts truck. It had a deluxe heater/ac that I took off to put on my project truck which is a 1963 c20. However through reading forums I thought these two years were common yet the lines do not look correct on my c20. Was the c20 different than the c10s look at picture below. Notice the line in ports for the ac are on the right of the picture. This is opposed to my 62 c10 which are on the box on the left. There is also a different style ac/heater on the 63 c20 any and all help appreciated thank you.