As for your assessments of the kit's IR jammer and canopy, you are correct on both -- I find them to both be poorly interpreted and mis-shaped.
Luckily for the ALQ, there is a much better version available in the resin Cobra Company set; or you can use the part from the MRC Kiowa Warrior kit.
Unluckily for the canopy, we're stuck with it for now. I do not believe it is from a J or T mod as you suggest, because with the exception of the Army's flat-paneled canopy, the USMC cockpit tub and canopy have remained relatively unchanged in their dimensions over the years.
I think that MRC just did a bad job of interpreting several dimensions on this kit. The kit canopy is too tall up front, and does not have the smooth, gradual curve that comes down over the gunner's head. At one time, I tried to test-fit one of Floyd Werner's 1/32nd scale vacform canopies for the AH-1G onto my 1/35 AH-1W. It did not fit close enough to be usable; but even during the test-fit, the vacform canopy improved the profile and overall look of the AH-1W from a distance by 110%.
Andy