1st Variant Powermaster 760

Good morning all,

This is my first post and not quite sure if its the right area to post this is in. Anyway, I recently picked up what i believe is a 1st Variant Powermaster 760. It wasn't working (pumping up) so I stripped the gun down and replaced the seals and got it working properly again. I was wondering if someone could tell me what year it was made in. It has a metal receiver, brass trigger and bolt, and wood stock and forearm. There is no year stamped on the end of the barrel band but there is a 56 stamped on the tongue groove on metal receiver where the stock attaches. 

Thanks!

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