They do seem to be the same site, but they are showing over 200 backlinks in Google and over 2,000 in Yahoo (which is closer to the real number). You would need to go through each of those links to find out why it is a PR7 (which I agree is quite irregular –or at least darn impressive– in this industry), they are likely linked somewhere to a PR8 or PR9, which is quite a feat in itself.
So much for the argument that PR is worthless, freeslots.com is ranked:
#1 for “online slots”
#9 for “video poker”
#2 for “free slots”
#8 for “slots”
And all of that with not that much content.