I have an original 81 model and the ball has never once gotten stuck between the downed targets since I've owned it for 30+ years. And I don't see any finger guards on it. You say the targets look as if they are sitting too low. On mine the bottom shelf of the drop target unit is adjustable up and down via slots in the shelf where the four screws mount, so you can raise/lower the 'down' position of the targets, you might check that out on yours. If the targets are too low I can see where the ball could easily get stuck.

If your targets really are too low and that is causing your issue, you could just remove the shelf and add a long thin shim of whatever material (metal, layers of thick tape etc.) to raise the targets. Me? I'd just lengthen the shelf holes vertically a little with a dremel so it's like the adjustable version and I'm not messing with different thicknesses of shimming and then attaching it.

If that's true then somebody must've installed a newer bank in mine, it has the slots. Or maybe the whole playfield was out of an LE that had socketed lamps, I dunno. I swapped in a new pf after I got it anyway.

Those fingers are nice but on mine just having the targets at the right level works for me, however one chooses to do it. Yes I can purposely place the ball between two downed targets and get it to stick there but I can't remember it ever happening during play, it's a very tiny and precarious perch. Versus say a ball getting hung at the top of a pop bumper ring and having to shake it loose, not so rare. I cannot get a ball to stick between a downed target and one that's up. The tops of the targets seem to have a slight downward slant to them too which helps.