Base Luger was not an artillery; 'standard' P08 rear toggle, no tangent rear sight on barrel. Looks like an amateur engraver practicing on an otherwise uncollectable P08 with a long barrel. The grips are especially hideous; I mistakenly bought a pair myself and threw them out after trying them on a few times.
Engraving a handgun is a way of hiding defects, same as floral enbossing on leather goods. Not all are pitted & rusty, maybe just normal wear or poor buffing/bluing. The engravings on this aren't the best; curves aren't smooth and lines aren't quite straight. The pictures aren't very good either - not enough detail.
A way to practice, maybe a 'feasibility study', to see if maybe the engraver was interested enough to put in the time and effort, and $$$ in tooling & jigs, to pursue this hobby. He seems to be experimenting with various styles/techniques.
IMO, $2500 is way out of line. I'm also particularly annoyed at the web site. It takes way too long to load.