Keg question

[strangebrew]

Well I was just looking at the keg I just got for free, 15.5 gallon size and got to thinking. I am wondering of it is made of SS or Aluminum. I know the one I use for me beer kettle is but this one I'm not sure of. I will certainly know once I cut into it but would like to know before hand. The reason being is that if it isn't I can swap with a friend on mine. He has a coors light keg I know is SS. The one i just got is an Anheuser Bush 15.5 keg, looks to be like the one's on sabco's web site, the grade B used ones from the mid 80's or some time around that. The sticker on the side states that it was last filled in 2000. Did AB ever use in that time frame anything other than SS? I will try to post a pic tommorw. Guess I'm just a little parinoid since it's not just going to be boiling water. Come hell or high water i'm sticking to the theme of Stainless Steel, Copper or Glasss else I ain't gonna use it!