Hi,
I've linked the document your requested below. The P/N you listed are for the kit you purchased so it does not match up exactly with the P/N on the documents. However, I have confirmed your kits include the devices listed on the documents I provided. If you look for the sticker on the devices themselves, you should find the P/N matching what's on the Letter of Volatility document.
NI VXI-USB: http://www.ni.com/pdf/manuals/374552a.pdf
NI PCI-GPIB: http://www.ni.com/pdf/manuals/376408a.pdf
James F.
Applications Engineer
National Instruments