I goofed in ordering. On this particular work machine, the CPU cooler doesn't sit on top of the RAM slots, but the HDD cage does. It closes fine over the RAM that came with the machine, but not over the replacement RAM I bought.
Most guides on removing heat spreaders say to take off the tabs, but I don't see any tabs on Mushkin Blackline heat spreaders. Do I pry? If so, from the top or the bottom? Do I use a hairdryer? Or stick them in the freezer?