Purists would want it all correct, and i share that view too. I have no idea about this rifle example.
A lovely boxed presented air rifle of this type, in fabulous authentic little used condition, has great appeal. As just a piece of gun engineering in the right setting, right gun room, then these kinds of objects are always going to fetch good money. Presentation case Luger or whatever, have a certain class and just lovely to own.
There are guns you use, and guns to admire. For any collection its nice to mix it up a bit, and presentation grade always look great. Price is how wealthy you are and to some two to three £K is normal for something they fancy. When there are those losing £40k on their Range Rover every three years, then what price gun that they like really is not an issue. Same for those who pay for a full season pheasant shooting. You earn it you buy the toys you fancy. Don't moan, get a better paid job, or buy a lottery ticket and live in hope. For those who can afford such luxuries, honestly earned, good luck to them.
There was a fantasic Webley Service Revolver the other year. I would loved to have owned it. Sadly I couldn't have afforded it at the time, plus wouldn't have been allowed to own it. No Sig 226, but it was just so pleasing to the eye and I loved it. Not allowing to be able to have it at all in this Country annoyed me most.