Okay so I did a little research myself on this transmission and I will get to what I came up with at the end. I currently have a C4 but I wanted a C6. There is a junkyard nearby with a C6 in a Galaxie.
Here is the codes/numbers I could get off of it. Very hard to read so the numbers might not be 100%. I just wanted to check with you guys first because I heard even if the 1 code says its a C6 the others might not match up? Someone told me that so I am trying to be safe here. So if anyone can confirm this is a C6 would be super so I can buy it

C6AP-7D027-C ( Located on the passenger side)
What I got from this? Its a 66(?) Galaxie C6 Automatic.

Now these other numbers I can barely read located on the drivers side.
From front of the transmission back.
D50F-AA
28A
*inside a circle like a carburetor venturi number (thanks 2+2 ha)* 6 -77
then here is the number I can not find anything about. It is located on the tail of the trans.
D4ZP7A040-AA