I think the updates are cumulative, so if your disc has a version previous to these updates, you need them both.
SB Pro PE 2.262---2006/04/30
SB Pro PE 2.273---2006/06/22
SB Pro PE 2.304---2006/11/13
SB Pro PE 2.328---
2007/01/23
SB Pro PE 2.328---Hotfix---
2007/05/22
SB Pro PE 2.370---Beta---2007/12/13
SB Pro PE 2.460---Upgrade---
2009/04/03
SB Pro PE 2.483---
2009/09/02
SB Pro PE 2.538---Upgrade---
2010/08/27
To be sure, ask again in the eSim forum.
Edit:
No, I am not sure anymore you need both, in the ordering section they list only the latest upgrade, not the first one anymore:
http://www.esimgames.com/purchase.htm
Which makes sense, because it is the complete sim with updated exe and stuff that gets delivered (without dongle).