Spanish M43 La Coruna 1951, 8x57 ?

[Aragorn243]

I would not do anything to the stock other than wipe it down. That's the way it's supposed to look. Stock sling mount is removed by removing the buttplate and then a pin or screw that is under it. The bayonet lug extension is so the bolo 1943 bayonet can be attached. It has the long muzzle ring relief. If you can find a Spanish K98 bayonet which isn't easy, you could mount that on it as is. They look like German K98 bayonets but are a bit rougher and no manufacturers marks.

Ammo "should" be 8mm but it's always wise to double check Spanish Mausers.