A work colleague has brought in an Original 35 .22 calibre, serial no - 99613

Doe's anyone know the age going off the serial number?

It's not too bad for an old 'un, a reblue wouldn't go amiss though, i't fitted with open sights and a scope.

I know nothing about these rifles, what sort of price range would it fall into, my colleague is pondering selling it.

What power levels do these achieve?

I know springs are available for them, but what about piston seals?

Are the piston seals leather or O rings?

Thanks in advance folks.