How do you tell what trans you have?

[The AntiRice]

i just got my 89 saleen clone and ive been dickin around doing small stuff ie o2 sensors, oil and filter change, msd coil and wires, plugs etc. anyway i had the car up on a lift and was looking at the trans and the cross member which looks to be stock (crossmember) so i wanted to replace the mounts and the crossmember itself. now heres the thing the guy i bought it from said it had a new tko in it so how do i tell if it really is a tko or just a t5 so i know which crossmember to buy? someone school me on foxbody transmissions and all the hardware that is associated with the driveline please.

 

[Aliate X]

if you move it side to side in neutral and it makes the clunking, its a stock transmission. If not its some sort of tremec.

 

[The AntiRice]

is there anyway to tell by looking at it on a lift? like some sort of number on the housing or anything like that?