2002 avalanche 1500 new shocks. do I need that metal post ?

So my 02 avalanche 1500 z71 just hit 100k miles and the factory shocks needed replacing. Ordered 4 new bilsteins and they arrived.  While taking the old front shocks off I noticed there is a metal tube that fits between the bushings.  The new bilsteins didnt come with that.  Is that something I need?  By the looks of it, it's part of the bushing.  Would a dealer carry this/these parts? 

got pics?

* I not my pic but this is what it looks like and is part of the bushing.  Not a sleeve. 

http://rs304.pbsrc.com/albums/nn172/Kamloops123/P1010471.jpg?w=480&h=480&fit=clip

https://www.moog-suspension-parts.com/moog-k6724

Part of bushing for sure....

Suggest getting new ones

well, after a few days of searching parts stores, i figured why not try the internet 

the part in question is, Dorman 905-500