I have an Original model 5 that i got for £100 just after the Covid business, It has the light tan colour plastic grips, from what I've seen online, it's an early to mid 70s piece. I think the leather seal had gone dry, it's only pushing the pellets around halfway down the barrel.. I'll have a go at stripping it and soaking the seal before summer is here.

Whoever buys your item will have lots of no nonsense fun with it, great for plinking, and enough power to end a rat!

Good luck!