These images on the HRP website are unfortunately not reflecting the current status of the HRP any more. I took those screenies back in August 2011 (i.e. with HRP v5.0), so you can imagine that some models changed, particularly the pistol. Also, Polymer and Polymost will sometimes use different models, and I have always used Polymer for screenies since it shows more eye candy.
If I'll get around to it, I will take new screenshots, but it may take a while since I am more involved with the addon compilation these days. The HRP also hasn't seen any major changes for a while now, so I had to move on to something else to keep myself busy.
I gotta admit I am not using the HRP any more by myself since ages. I also stopped doing that for Quake or Doom. Even the best attempt to imitate vanilla textures and sprites is still never going to deliver the same atmosphere as in lowres, at least as far as I am concerned. HRP is still a nice thing to demonstrate some of the enhancements possible with EDuke32, though.