I actually got a great deal on one of these drives back in November during the holiday rush weekend. Office Depot had the 45GB Maxtors for $119. No rebate, nothing.. just $119. Plus, the free Promise ATA-100 controller. I still can't believe it.
Anyways, as far as the 5GB free sticker goes, I'm almost positive that if it doesn't have it, then you're not going to get the extra space. However, you most likely will get a newer DiamondMax Plus 45 (40GB version-model 54098H6). The Plus 45 is the newer 15GB per platter version of their hard drives. The older drives were DiamondMax Plus 40's, which had 10GB/platter. The Plus 45's are slightly faster, and produce less vibration. They're very quiet and very fast. And they make absolutely no noise when seeking. I have another system with a Plus 40 and it makes more noise and vibration due to the extra platter, I presume.
So, even if you don't get the 45GB version, you'll most likely get one of the newer 40.9GB Plus 45 drives.