1972-73 GT550 center/lower exhaust pipe question

[2strokelove]

Ok, this is going to drive me crazy. Exhaust on these GT550's like to drive me crazy!! I know that the outer pipes are not the same from the 72/73 to the later 74 and up. But are the center/lower pipes also different? I just purchased a late 72 early 73 Gt550. Its the gold model with the double front brake hub. I thought the exhaust was original, but now not sure. First the outer pipes have the tabs at the cross-over pipe for the springs. The center pipe does not? am pretty sure that the 72 didn't have the springs on the cross-over tubes. So now the lower pipes. I thought they were correct but now not sure either. Mine are missing the tab that would have the rubber bumper on it to cushion the center stand. My outer pipes also do not have a rubber bumper. So what cushions the center stand when it slams up. One other difference I notice is the hangers on mine are solid, others I have seen have a hollow cut out in it. Any explanations would be greatly appreciated!!

[Coyote]

There are no springs depicted on the 72 and 73 fiche. But the hangers do have the cutouts. Sounds like someone has replaced the outer pipes with the later model pipes. The mounts are different so maybe the original mounts were cut off and home fabricated mounts were welded on. There should be evidence of that though. Like old grind marks or welds near the mounts. I think the difference is about 1 1/2 inches. The mounts (hangers) are not stock without the cutouts.
Thanks for the compliments on my bike!

[2strokelove]

Both center pipes look original. No signs of any grinding or welding. The frame of the bike has not been messed with either?? I did see a set of 74 center pipes on ebay that had solid hangers on the lower center pipes. The pipes were on the bike when I got it a week ago. They were mounted wrong as the P/O had a pipe on each side of the hanger. So the pipes looked like they were 4' wide!! I moved them to correct location and all looked ok?? Baffles me

[Coyote]

1976. Outer mounts are solid. Inner mounts have the cutouts