If the computer does not have Group Policy included to look at, then you can edit (right click on REG file and click on Edit) the REG file downloads in OPTION TWO of the tutorial below, then check the registry and compare it to the REG file downloads to see how it set. By default, it is set to 128-bit with diffuser in Windows 7.
I see what your saying about the group policy, I'm not quite sure how the REG file works, whether its used just as a reference to the encryption level set by the Group Policy or just another way to set the desired encryption strength before encrypting.
I guess my overall concern/question is that say someone else encrypted a portable drive on Laptop (A) and gave the drive to Laptop (B) to mount and authenticate, is there a way for Laptop (B) to see the encryption level that was set by Laptop (A)
You'll need to look at the settings on the same computer that you want to see if it's using 128-bit and 256-bit encryption keys, and not from another computer. By default, Vista and Windows 7 uses 128-bit unless manually changed.