But now that if it came with a thermal pad, you need to keep using a thermal pad! Be sure to match the thickness. (tape is fairly sticky, pad is not.(well, a liiitle bit..but not enough to hold stuff on properly.))

It is more likely they used a thermal pad, actually. Since the heatsink has other means of mounting(screws) and it is rather big. Normally tape is only used on small stuff like ramsinks.