For 1972, if one ordered a 442 non W30 with a 455 auto, it was the U code designation, correct? Also, if the W30 option was ordered, the W25 hood was part of the package, right? IOW, the W30 was not available without the W25 hood, or was it?

 

X denoted the W30 and the W25 was included with W30.package. 455 auto wa the U code and the stick was V code.

 

Take a look at this post for more information: 1972 U, V and X codes?

 

Gotcha...so the U code 455 was no different in the base 442 as the one used in other '72 A bodies, correct?

 

Except for W-cars, all A-body 455 installations with automatic were the U-code 250 HP L75 motor. All A-body 455 installations with MT were the V-code 270 HP L75 motor. The primary differences were the cam and the valve sizes.
L75 MT motors got big valves and the 409691 cam with 286/287 deg duration and 61 deg overlap (the same cam used in the AT L77 W30 motors, by the way).
The L75 AT motors got small valves and the 402486 cam with 258/272 deg duration and 44 deg overlap.
For completeness the L77 W30 MT got the 409759 cam with 294/296 deg duration and 68 deg overlap.