Info about Windows 2003 Device cals & Terminal server Licenses

Somebody has asked me to setup some new boxed spare Dell servers, purchased in 2006.  The problem is that they only have 2GB memory and are only needed to perform very minor basic server functions.  

I was advised that Windows 2008 will not run because of lack of memory so we are stuck with Windows 2003.  I tried to order some device CALs and Terminal server licenses and was told that these products are no longer supplied by Microsoft. (Which is sad as the MS site says 2003 will be supported until 2018.)

Last time I loaded additional licences onto Windows 2000 Server I was able to add the licences without the need to enter any codes or anything.  Can I do the same with 2003 device CALs and  TS CALS?  Or can I used 2008 device/TS CALs?

PS The client has suggested that if these CALs are simply not available we may have to use Linux; I cannot believe that this is what MS indented?