thundergod is mixing variants. The circular sight (CITV) is only found on the M1A2 or M1A2SEP. The 8-tubed smoke grenade launcher is a USMC item and would be incorrect for a US Army tank. Additionally, if the coax tube was missing from the right side of the gun tube, that was probably battle damage (or it just broke off) since it is little more than a steel tube welded to some cooling fins.
There was a pretty good mix of early M1A1s and late M1As (what folks call M1A1HA) in the first Gulf War, but during OIF, the M1A1"HA" was the only US tank rolling until the 4th ID showed up with M1A2SEPs.