What xausa said.

But its the lines (...and the grip cap! ...and the 'Jetsons' cheek-piece!) not the side-panels that give it away.

Remember, Westley Richards made great use of side-panels on their big game rifles, doubtless borrowed from European sporters at the time, and probably for the same reason as did the re-stocker of this .404.

Side panels reinforce the stock at its weakest point, through the thin sides that have been inlet for the action and relieved for the magazine box. Many of these big kickers have a recoil lug ahead of the action, and with no cross-bolts the force of recoil is carried back through the stock-wood.