Hi Joe,
I may be wrong, but that looks like an Australian huntsman spider on his right leg.
IIRC, they were mascots of one or two Highlander Bns.
Truth be known, the only thing I can say with certainty, is that:
either- two of them aren't wearing hats,
or- they wore stealth berets.
EDIT:
No problem about 51st and 53rd; one is quoted as Division, one as Battalion. A Division is 10,000 to 30,000 men, whereas a Battalion is only 300 - 800.
If I can be of any further help, you can write questions on your paper napkin when you come for supper.
![smile :)](./images/smilies/smile.gif)