They are worth what someone will pay for them. Personally, I wouldn't give more than about 20 bucks for them. I have about 4 of those style...5000's...6000's...and I have a 5000 series that came in the walnut box with a gold plated reel (don't get excited about the 700 dollar value on it, my old man used the hell out of that reel, LOL and I still fish with it).
I wouldn't pay more than about 20 for these because they are older technology and I have several of them (they are worth more). Its difficult to find parts for them...but...ive never needed a part for them in 30 years so....
Your 5000D is a special kind of reel. It is a direct drive. You can't horse a fish with that one like you can the 'regular' ones, you will break the line. Pull the line, the handle spins backwards. May not be worth any more really. In case you don't know, that knurled drag knob is designed to apply very little drag resistance with your FINGERS...don't use pliers to get it tight. Its not supposed to be. I had to fix my buddies because he used pliers.
When I fish saltwater, I actually prefer the older ones like you have in your post. They aren't necessarily smoother than new Abu's but they cast further....I use them side by side. Plus...there is a lot of brass and metal in them that holds up better than the new ones with all the damn bearings. Those bearings will rust and they will swell and you will destroy a reel removing them if you arent careful (these are the 15 dollar craigslist specials that I love). The new ones are great if you take care of them.
For the older ones, Id say 40-50 is a good price if they are in functional condition with some boat rash. 60-100 if they are even nicer and you snag some sort of collector. My hobby is buying any abu for about 15-20 bucks in 'broken' condition and then repairing or frankensteining them out of my parts bin. Its fun and you may have a reel with multiple colored sideplates but it works like new. LOL.
They are great reels though. That's what I started fishing on and there is no Shimano that will change my mind at this point. (my Calcutta has never seen the water)
Edit: That 4000 series reel with braided line is the f-ing bomb. Light line, small bait..you can cast it to China. Seriously.