When he built it new it might have cost him $2000. Depreciation on a rifle is real as it is in cars.
I've not found there to be any depretiation in any top end firearm, quite the contrary! That gun 20 years ago no way cost 5k to build! That's the cost today for a new Bat on a custom Carbon fiber stock and Krieger Barrel with a B&A trigger.
I'm betting when that rifle was new it cost about $2000.00 to build. Fact is my first br build was on a XP-100, with a Hall stock, and a custom Merideth paint and bedding job. Over 30 years ago and that's about what I had in it.
Now add all the stuff to prep brass, dies to load, bullets brass primers powders and the type of bench rest equipment to shoot off of ,,,, ya you can more than double the cost of the rifle to start competing. But 5k will get you the best BR rifle built today, and that's more than double what that rifle would of cost. About the time folks quit sleeving Remingtons for increased bedding area.
Most guns I bought 30, even 20 years ago are over twice the price they cost back then. I remember when folks said a Ruger Black Hawk would never be worth more than 300 bucks, 3 of mine in less than 20 years are worth over 1500 bucks today. Freedom arms price one of them today, my first was a 454 at around 1k. You can double that for it today.
Good, high quality guns have always been a great investment, and that won't change as the price of New continues to sore, and top gunsmith continue climb with labor costs.
Just my personal experiance,,