Replacement Dash Harness

Our Barracuda was torn down in the early 90s and the complete dash was stored in our conditioned basement. OD says 16k miles, no reason to believe it was 116k, so everything was fairly lightly used in that respect. I'm rebuilding the dash now and trying to determine the need for a replacement harness. The original appears to be in great shape, not spliced in any way. I plan to have a disconnect from the battery anytime the car is in storage, but curious what the general consensus is on replacing the harness. Is it an absolute simply given the age or a need by need basis?

That's low mileage = little use if it's really 16K & mostly indoors.
If the connectors & terminals look nice, and the wiring isn't brittle, should be fine.
You could do a resistance test.

Thanks for that feedback, that was my thought as well. Wires feel like new, connectors feel tight, very little if any corrosion on anything that I can get my eyes on.

one place to look very carefully at, no matter the age [or mileage] is the connection at the bottom of the steering column.
i have seen, and repaired, MANY of those connectors because they get hot and melt.
dodge, chrysler, or plymouth, it doesn't seem to matter. for some reason, [and i suspect vibration as the instigator] the earlier models with just the turn signal switch and horn, are not too bad for this, but it still happens.
however, when the key went into the column, those connections really started to show "meltyness" problems.
hopefully, the OP's connection is good there. if so, it still should be taken apart and the crimps should be checked for tightness as well as the male and female pins fitting together tightly.
after that inspection, with all being good, add a dab of die-electric grease to the connections before plugging them together.

Agreed, I'll be sure to look over the steering connector with heightened concern, good suggestion.

Exactly the place I had problems with my 71 Challenger R/T. It would over charge and the ammeter would bounce around and it would pop the tops off the battery! I could not find the problem. Three garages could not find it. One day I was laying on the floor under the steering column just looking around. I saw a big black streak in the connector that goes to the steering column. The heavy "hot" wire was melted together and burned. I could not get the connection apart.
So I just clipped the two wires off and butt connected them. That fixed my charging issue.

those are called "MOLLEX" connectors if i remember right.
the two sizes used are .093 and .125, again if i remember correctly.
the kits can be bought in several places, as well as the individual items.
i make sure i have all of the items needed on hand because this is such a common problem.
one thing to make DAM sure of when replacing each of the connectors. when you are done with your crimp, look at the mating surfaces and be SURE they are ROUND.
if they are not, just the sides of the terminals will touch, which means the current flow is only through two VERY THIN contact points. resistance is up, heat is caused, and we all know what happens next.
i can't stress this enough. it is especially critical on the female side, and when you push the connectors together, make SURE you push them together STRAIGHT.
if you fight them, there is a very good chance one or more of the female terminals will get egg shaped.
this is probably one of the reasons the newer stuff went to those tiny spade type with the flap on the female side, to ensure a tight connection at the column.

Another spot to check is the bulkhead where the heavy wire that goes to the ammeter comes in , a poor connection in this spot causes the wire to overheat , it's caused by resistance buildup in the connection itself . it can get hot enough to melt the bulk head . sometime in the late 70's/early 80's Chrysler finally realized this was an issue and made this wire pass thru the firewall without connectors.

As mentioned above, MOLEX are the correct terminals to use and are as far as i know they are still made today. When i did my car years back i had to get them to fix/restore a few harnesses. However if i remember correctly you have to use a MOLEX style crimp tool if you are looking for the correct look. Excellent point above on making sure everything is round for a good connection. Also make sure the small barbs are sticking out so the terminal fights tightly in the plastic housing.