If the offset of your front and back wheels -- the link I saw made no mention -- are 38mm, I think you should be okay. The rear wheels may be close.
Please be aware
offset and
backspacing are two different things. Here's a link for that:
http://www.rsracing.com/tech-wheel.html
The new drums shouldn't add any width but I would double-check to be sure. Then with your current rear wheel off, you should be able to measure and calculate whether you have met that tolerance. Make sure you get the data right from the manufacturers.