Automatic shifter assembly help screws needed

When I got the truck the orange shift indicator piece of plastic that's supposed to show what gear you're in was not attached to anything, and neither was the P/R/N/D/2/L piece of plastic either. Oh AND when I took the big top cover piece off I also found a green & black piece of plastic that's supposed to fit in somewhere, too. Here's some pics: (yay pics!)

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Ok so I have the top cover for all that and it's just not in the pics right now. The problem is that the little screws that hold on the plastic shifter letters P/R/N/D/2/L piece and the blank black piece on the opposite side of the shifter, are ALL missing. There are apparently at least 4 screws missing because I found 4, (maybe 6 I can't remember right now) empty holes in the bottom of the big black cover piece that goes over all this mess. I've searched all over and under the carpet & couldn't find any extra screws laying around.

Does anyone happen to know what size/thread type those screws are supposed to be? (long shot I know, but just in case)

And yes, I'm going to clean the hell out of that area because o-m-g some people are gross messy with their trucks :( There's even dog hair (I think?!) down there. I pulled out cigarette butts already :( It's so nasty!!!

Oh and also, if I take off the top of the automatic shifter will something break? LOL!!! I was thinking I could take the big plastic piece off and into Ace hardware to see if they could identify the screw threads, but it won't come off over the shifter handle. There's a set screw in there holding the shift handle on but if I take that off, I'm worried about what I may find & have problems re-connecting the handle --- because there's that button up there on the side, it must be attached to something, maybe a cable, maybe a tension cable? I'm too chicken to take it off to find out at this point.

I can't believe finding screws can be this hard. I'm going to go look again while I clean this area out.
Big thanks in advance for any tips about this darn thing.

Okay so it's a 4mm screw, at least that's what worked, along with a lock washer & regular washer. As I was pulling back carpet around the shifter assembly I found a very tiny semi-rusty old screw w/ a lock washer & regular washer on it. PURE LUCK! Took it up to Ace Hardware to see if they could make a match & very thankful for the oldest guy at Ace Hardware for finding a close enough match. A little longer but still fit in the holes just fine.

I spent the better part of today cleaning the heck out of the whole area & all the pieces, then finding a little light bulb to fit in there & getting it all back together. Good grief it was a pain to keep everything straight while screwing the screws in upside down. Ugh. Anyway, we'll see if the bulb works or not after I get the fuse box back together & neg. cable back on the battery. It still seems to shift just fine & the letters are all lined up with the orange indicator, so so far so good :)