Out of curiosity, I decided to load up Pool of Radiance, create a Female Human Cleric, then hex edit the gender field to a value of 2. (0 = Male, 1 = Female, offset 9E) Here are the results:

The character's gender was displayed as "COPPER". (Probably the next text string in that part of the game's memory.)

When Modifying the character:

Minimum Strength is 18. (Yes, that's the minimum, not the maximum.)
Maximum Strength is 100.
Strength 25 gives +14 to damage on the character sheet. (Is it possible to raise Strength that high normally?)
Strength 26+ gives no damage bonus on the character sheet. I don't know what the encumbrance limit is.

The highest legitimately possible Strength score throughout the game, in the absence of bugs, cheating, or the use of hacked FRUA mods, is 24.

Of magical effects available in the games:
Girdles of Giant Strength in the Gold Box games mostly offer 23 STR, with the exceptions of the ones in Champions of Krynn (21 STR) and in Curse of the Azure Bonds (24 STR).
The Enlarge spell IIRC maxes out at a STR of 22 even at high mage levels.
The Strength spell maxes out at the normal racial maxima (and therefore at 18/00 for any normally accessible race/class combination, which is why it is pretty much totally worthless in the GB games, Enlarge is always better).
I'm foggy on what the Potion of Giant Strength gives offhand, but I seem to recall it's 21?

At least one bug can create Strength scores all the way to 100 (the Pool to Curse import bug I've mentioned a few times here). However, scores above 25 are unimplemented and worthless; any data effects you're seeing is essentially random garbage (basically the game is reading whatever happens to be at the memory indices that *would* be correct for that score, had data actually existed for them).

If this were the case, I would expect to see strange non-zero values, some large, some negative (some both?), but I only saw zeros.

Because the Gold Box games are based on 1st/2nd edition, where there is no definition of stat values above 25.

Also remember that there were minor code changes to each Gold Box game, so not all behavior may be identical.

There was a Potion of Giant Strength in Pool of Radiance, for instance, but no girdles.