Stanton your first attempt was extremely close, But no coconut! The real explanation is this, on very large estates where this peg selector came from in fact it was made on the estate with the "X" being the give away and not just having numbers only. Back in Victorian Edwardian tines such large estates had a good number of "Tennent Farmers" with the tradition at that time was to have a Boxing Day Tennent's Shoot and that is where the "X" came in. Depending on how many Tennent Farmer's where invited and this estate could handle up to ten. The keepers would be instructed to lay out ten shooting stand pegs, then either the number 5 or 6 token' was removed from the draw either numbers being the centre of the lay out giving the best shooting position usually and the "X token added. When the peg draw was done the lucky person with the "X" would get a good peg position also on the estate where this peg set came from the lucky Tennent would also receive a hamper containing seasonal luxury foods I do like to think it was a Harrods hamper plus a bottle of Sloe Gin. The same form of selection method was also used for Keeper and good friend shoots. Alas a lot of these large estates now have been broken up and sold off putting an end to this tradition though I have been told that on some Royal Estates something similar still goes on.
Ernie.