Help! Mk 6 Meteor expert sought!

[laverdabru]

Just got, in well under 24 hours - pat on the back to PF! - my late b'day present. Very well packed by the previous owner.
On assembling the action into the stock there's a bit left over...A 1cm x 3mm black plastic/rubber disc.
Mailed the po - he found it on the floor after dissembling the stock from the action.

To quote - hope he doesn't mind That small rubber disc was on the floor when I was packaging the rifle.
I wasn't sure if it fell from the stock when I separated the action or if it was something from my daughters craft stuff.
Looked but couldn't see any contact marks where it might have been.
The other spacer that fell out from inside of stock I put back in with a dab of glue so it didnt get lost again.

Looking at the exploded diagram, there are 2 parts at the forend of the stock, parts no's W102 (lever Support Cup) & W103 (Lever Cup Rubber) I'm wondering if this is the part that's meant to sit under the cup rubber, if you see what I mean.

And while I'm re - asking, are there any pellet preferences for the Mk6?

Any advice gratefully received!

Thanks in advance

Bru