Jonathan, I don't know what the rings are made of, but you can save yourself alot of money if you get them from Rockauto...
I went to the IH stealership because they usually are reasonable and even cheaper than the Ford stealership and paid 52 bux for the full set and the Ford guys wanted 55...
Frack that... I thought that was frelling disgusting after I found out that Rockauto wants less than
7 bucks for them...
Go to Rockauto dot com and type part# GS33545 in the search box at the near top of the page.
They are Victor-Reinz and are very good quality seals... In fact, I used the same in mine just weeks ago...
A word of advice,
DON'T hit the oil cooler ends with a metal hammer... I did out of frustration...