FIXED IT UPDATE ..... I received the spring, just got it installed. Not a perfect fit per se. It sticks up just a tiny bit into the magazine channel and drags just a tiny bit on the magazine, which prevents the magazine from smoothly dropping down & out.
If I find the energy, I may remove the spring and bend the long leg down just a tad, that seems to be why the left-side edge sticks up a tiny bit.
But for now, the fixit works just fine and the P90 is back in business.
FlyerTom,
You are right, that's a tiny spring in the plastic bag, I had to hunt to find it.
Only one hole in my latch. Instead of a mouth guard, I clamped the pistol frame muzzle-pointing-down in the vise, so I only needed two hands. For better or worse, no swearing required for this particular installation.
GENERAL QUESTION: The concept of 2 holes in the latch: do you suppose that's how the "obviously ambidextrous" latch is changed so as to change the latch for the left-handed shooter, so he/she can use their left-hand thumb to depress the latch from the right side of the pistol ??
Cheers,
Carl