I was rereading Metamorphosis Alpha the other day (the 1976 version, in case you were wondering) and I came across a little table in the "Distribution of Monsters (Mutations) and Treasure" section. It was a simple stocking table, requiring a roll of 1d6 in order to determine the contents of a given room/chamber/area.
I've been spending a lot of time running probabilities over at AnyDice 2 lately. As such, Ward's probabilities looked a little sketchy to me. The table had 4 entries, giving two entries at 33.34% and two at 16.67%. I suppose that's fine, but I could see it having a little more granularity. Here's my take on Ward's table:
d10 Stocking Table
1-5 monster only
6-7 monster and small treasure
8-9 monster and good treasure
10 very strong monster and good treasure
Fifty-fifty seems like good odds for there being any sort of treasure at all. Of course, this particular table discounts the possibility of treasures occurring without monsters. In my estimation that's not really a bad thing.