Does the XBOX 360 controller have pressure sensitive buttons

Solution 1:

The Xbox 360 controller does not have pressure sensitive face buttons. The only pressure sensitive inputs are the analog sticks and the triggers. The issues this causes for games developed for other platforms is a common complaint - notably Metal Gear Solid games, as you've mentioned.

Wikipedia even mentions this in their article about gamepads:

[On the Xbox 360 controller,] the pressure-sensitivity feature on the face buttons was removed, making some original Xbox games, such as Metal Gear Solid 2, unplayable.

Solution 2:

Decided to answer my own question 6 years and 6 months later, as this game has just been re-released on XBOX One via backwards compatibility!

It turns out you can click the left analogue stick to raise/lower your weapon in first person view.

• Click once in first person view to raise active weapon
• While raised, press X to fire
• Click again to lower active weapon
• If active weapon is raised by holding down X, click once to lower it