[Stealhead]

I can say with 100% certainty that that is an early Mauser pattern bayonet the exact type though hard to say in that condition. It may be a Spanish Mauser as well darn near the same except for different markings.

I can think of three Mauser bayonets that have nearly same basic pattern Chilean, Spanish and Yugoslavian. Though logic would dictate that most likely its a Yugo. I forgot Polish and Czech so it could easily be one of those two come to think of it.

In this case due to contion the scabbard will be the best indicator doubt that you can make out any markings on the blade itself.

I'd use just two screws as all the old Mauser pattern used two but up to you I recon.