73 VS 74 Duster Front Bumper Differences.

Buddy of mine with a 74 Duster swapped his original front bumper as a core for a rechromed one with a California rechrome shop a few months ago. He just tried to install the purchased one and found that it would not fit his 74. He called the shop and they promptly blamed him for the issue saying he gave them a 73 and they gave my buddy a true 74. I see in my interchange manual that till mid November of 73 , for the 74 model year, they used the 73 bumper. His car's build date is 4/74. Well after that. It appears the rechrome guys gave him a 73 and took his 74. Anyone have this issue in the past or know the mounting differences between a 73 and 74? I owned this car for a few years and the previous guy had it a long time. I know this is the original 74 my buddy sent the rechrome guys. Car has never been hit in the front.

Thanks!