Hello JWhipple,
If you are not using the product key number for the 32 bit retail Upgrade Vista installation DVD, then you could use it to do a clean install with the upgrade DVD instead if you like. This tutorial will help show you how to if needed.
Clean Install From Upgrade Vista
Since the other one is a retail version, you could order the 64 bit DVD version of it for around $9.99 S&H directly from Microsoft and use it instead with the 32 bit retail upgrade product key number to install.
Windows Vista Alternate Media
Hope this helps,
Shawn