I have noticed quite a few variation on the tan interior cars. Lots of variation and mis matched colors.
Do we have any photos of what we believe is correct?

While it looks pleasing on the eyes to have a uniformly matching interior, some mopars right from the factory had various shades on "matching" interior components, some rather glaring at times, it was probably due to various vendors, bottom of the barrel dye pigments, different texture/base color of components being dyed... host of variables

That is true, How does one then assemble a "factory correct" car? Mismatch or correct the mistake. I mean which is correct in the eyes of the judges?

Depends on which judges you ask.

I do not have a Mopar Tan interior, but I have a GM tan interior car. ('79 Trans Am)
There is quite the mis-match in the tan pieces on the Trans Am as well - and not because of aging or sun fading. I think that the different materials play a large part in how the color appears. Whether it is a plastic piece, vinyl, cloth, or leather. Some cars have a mix of all of those materials - and thus they all look a little bit different!

The judges are not the owner nor the driver of the vehicle, do what suits YOU....personally I correct "serious" shade variations, leaving barely noticeable variations, IMHO if it all matches "perfectly" it looks contrived or an amateur's attempt at spray dyeing everything no matter how nice it looks

I have a buddy that has a tan interior cuda. He had a very hard time getting seat covers that were even remotely close to the factory shade. Legendary sent him the first set and the insert was so far off , it looked gold. The rest looked ok, but not exactly matched. I have and old set of tan seats that have been out of the car and inside so they are not faded, just brittle and worn out like a ten year old set of seats. I had to send them a piece of my insert before they could even get close. It looks ok but the factory seats match much better. They just don’t have the correct color of material now days and will try and sell you what they have. At least they take them back and try to match them.

On an original Mopar there are subtle color differences between interior parts to give some contrast. I saw a '69 Roadrunner that the owner had dyed/painted all of the black interior pieces the same gloss and color. Really blah and frankly, unattractive.

I have allways get confused on some "white off" interiors being really tan... and backwards. Sure, the pictures on web don't help.

My brother recently finished up his 70 Challenger with a green interior, for starters he had the 'bayou green' paint mixed with the codes taken from the 1970 parts catalog, and redid all of his interior metal pieces, dash frame, steering column, etc. as called out on the same page of the catalog. He also had SEM vinyl dye mixed to match the paint and sprayed that on his dash pad, console, door & kick panels, seat backs, rear package tray, etc. IMO the result looks really nice and coherent, would it be totally correct, no, but the carpet, seat covers, headliner still do provide some of the color variations.

I guess in hindsight, mixing up a few similar but different shades of dye for the various soft parts would yield the most authentic result, short of using all NOS parts- which would seem to be almost impossible these days.

The car in question is a 70 Challenger its an October build and the build sheet says H6T5 so Interior is T5 which is a 69 color and not listed as a 70 color. Its super bright and wondering if this is a mistake or correct as nothing really matches otherwise?

H6T5 is a legit 1970 interior code, see the page at https://www.hamtramck-historical.com/images/dealerships/colorAndTrim/1970/70_Challenger0003.jpg

H - High price class.

6 - Vinyl seats

T5 - Tan

And.... this is not 'E body' only, note the original tan interior in my 1970 Dart Swinger, several shades of tan & this interior was all original down to the carpet;

Thanks Barry but I guess what I am asking is the other trim is indicating that it be painted T5 and that is looking really "coppery" It is having me second guess painting it that way. Horn pad is T4