I have a 450 Bushmaster (factory, not build) and want to change the A2 type stock it came with to a AR-15 ARFX Skeleton Stock. See link below for the one I'm looking at.
Will I need to get the Tube, Spring, and assembly, or can I use what is in the A2 type stock it came with?

Don't mind opinions for other stock options, but I do want to change out the A2 type it came with.

Thanks in advance

AR-15 ARFX Skeleton Stock

Windage & Elevation