Hug survivor
Welcome. As you may expect, there will be plenty of opinions on this. I'll throw some in... as someone who also felt that, although the exterior had been painted (1X) and the motor swapped (2X), the interior had been kept stock and in presentable condition. As the project scope crept larger and larger, I ended up having similar thoughts. How much to keep as-is, how much to replace as-stock, how much to upgrade, etc...
Your intent or "exit strategy" is not yet apparent. Me, my car was Dad's from new and isn't going anywhere in MY time. My kids will have to make a choice. You, you may wish to have it a long time, or might prefer to profit from your find... no sweat with either, but it would definitely play a role in your next decisions.
Many here will ask questions regarding Event categories you may intend to prepare the car for: Survivor, Stock, Personalize, Modified. Each regional club may also have their own detailed rules for these categories.
As has already been stated, "Can only be original once..." We can't see the car and therefore can't make judgment calls on how near to any of these categories you may be.
To that, I'd strongly recommend, regardless of your final intent, to seek the 'council' of a TAC inspector team to document the car and perhaps ask them (3 + are needed for a certification) for their own opinions* after their review.
And... I'd do this RIGHT away, before you even really touch it. I'm serious. Take hundreds of photographs of the current state of the car regardless. You'll not realize how important this may become. If it really is a decent survivor, this could be helpful not only to you but to many of us...
I was probably more diligent about photos and cataloging than many, but still...you always wish you had another angle, etc. Lol... I most certainly removed some items without diligent concern and have harmed my best chance to get it back to 'correct.' I also blew some communication with the service folks that have handled the car, this also could have been avoided. EX: Hey, media blast guys, please do help remove or mask certain areas better than I have.
Of course, we're all dying to see the car, please review the link in the earlier post. OR, I'd be happy to help as well... send me a mail or "PM' on here. The moderators would also be pleased to help.
RE: Computer / Pop-up Image files. Close that window entirely. Close the forum tab in the browser. Try again. Make sure that each file has its own name. If taken with iPhone it may not be. This creates issue of only being able to upload one image at a time.