firstoldsmobile

Hey out there. It's been a little while since I've been on any forum. I'd mentioned a several years ago on this forum that I'd owned - fixed up and had sold around 7 to 8 AMC cars from around the years 2000 to 2014. They were rare and cool but NOT WORTH ANYTHING monitory wise.
After selling the last one at that time I've now bought and sold a 1988 Cutlass Supreme Classic, 1986 442, 1979 Hurst Olds Clone, 1979 Hurst Olds real one and sold within the last 2 moths a really rare 1980 442. After promising that car was the THE car I was going to keep at least until I retired, my wife said no more restoring cars. At 58 and limited time because of my job, I'm a PGA Club Professional so in the winter months in S.C. is about the only slow time there is, she said it's too difficult to meet a time deadline by March each year.
So what happens next? A customer says he wants to sell his son's 1988 Cutlass Supreme Classic 80,000 original mile car bought new locally. Sounds awesome doesn't it, but there's always a catch, an upside and downside.
The Upsides it's loaded. Bucket seat, console, rally gauge, power windows, power seat, power door locks, t-tops, cruise control, sport steering wheel, SS1 chrome rally wheels etc. Can't think of a thing that wasn't checked off option wise. Have the dealer invoice and under the back seat was the build sheet for the interior color, cloth etc. Unfortunately the normal build sheet wasn't there, nor behind the seat backs, headliner board, nor anywhere else. The dealer invoice showed $17,000 and some change. That was a lot of money for then. Floors, trunk, rockers really good only around the edges of the T-tops it rusted of course, those things suck. Despite sitting outside since 2006!! the interior is ridiculously good. The molding trim had not one piece dry rotted or cracked and the cloth seats were almost perfect.
The downside. I didn't figure I could just change the fluids, plugs, put a battery in it and it would be good to go like you see on YouTube. Gas tank shot and sending unit (amazingly the fuel lines were perfect), carburetor shot, front bearings shot, (pads were great), rear shocks shot. After fixing all this car runs almost perfect. Even the air conditioning still works which is a minor miracle.
Here is my question, since I promised that this was the car I was going to keep for me. On a strictly value sense for resale for when I'm a really older guy, would this car be worth more going back to truly stock?
Has a vinyl top and all the lower rocker trim and single exhaust. If I rocker trim delete, vinyl top delete and install dual exhaust, would it hurt the value of this one owner car?
Thanks for letting me ramble.

olds 307 and 403

No, I would not worry about keeping it stock, anything but a performance model, the H/O or 442 has very limited value. It should have all the options codes inside the trunk lid, my 88 CSC did. Hopefully someone checked off the F41 suspension option. Without it, those cars handle terribly, mine didn't have it, was like a washing machine around the corners. Check for the axle option code, it will have either 2.56 or 3.08 gears, most got the 2.56, mine did with an open diff. The factory TH2004R had 3000 rpm full throttle upshifts, even low for the swirl port 307. Very comfy cars and very sedate stock. Good luck, modify with your hearts content.