Thanks for the heads-up, Geoff. I'll run a check on eBay for the compass.
Regarding the change over to mills - my recollection (fuzzy) is that it was in the late 1950s, perhaps as late as 1958-59. For some reason, it sticks in my mind that the 81 mortar guys were the first to use mills. (in the infantry) Don't know about the 105 and 155 guys. And of course, this is admittedly fuzzy recollection at best.