It has all the hallmarks of being the real thing.The cross guard is just bent on the blade side.Ive never seen a pommel like that on m3's but it all looks good to me with the Ordnance stamp.Nice classic knife.
On some well used knives the leather grip washers have shrunk
so someone bent the crossguard to prevent it from wobbling.
The double tang pommel is a variation.
Boker M3's are harder to find. It's a bit beaten up,
but still nice.........!
I would concur with Steve's assessment. I would only add the double tanged version of your knife is the earlier of the two blade marked variations. That said the "salty" condition that it is in would seriously impact its value/worth. It would take quite a bit of effort to take a reproduction and turn it into what you currently possess and for a marginal (if any) increase in value. Thank you for posting it.
It is a good one.
I agree with those who have already posted, you did well.