there is the proper amount of space (7 3/4 inches) between the barrel-band and the receiver.
...
If I had to guess, I'd guess it's a genuine No.5 which had been sporterized at some point and later semi-restored ...
-- David
Neglected to mention that that the squared metal cap to the fore-end is missing, and the wood there has been rounded off, suggesting an original No.5 stock, sporterized at one time.