I think it's a fair price too. I had both .177 and .22 both boxed with everything as they came out the factory. The .22 was number 2, and the .177 number
235.
When I sold them I got £950 each.
My mate Simmo on here had one like yours and sold that for £625 if I remember rightly, so your price is fair.
For me, what let the centenary down was the stock, it was a poor piece of timber on what could have been a stunning rifle. These were mine
https://www.flickr.com/photos/124581.../shares/T5uE89
Fozzy