Hiya Scott!!
I'll give you the answers that I know, how correct they are...well... there's some speculation there.
Decoding the VIN is not going to be much of a help because there weren't too many options that year. By 69 the t-bird came pretty much loaded. Landau top, color and interior trim were the total choice you had by that time.
The 69 only had a 429ci big block that was rated at 360hp with 405 lbs/ft of torque. It only came with a 429 to get around some of the emissions standards that were rearing their ugly head at the time.
The C-6, 3sp auto was the only trans available by that time and it was solid enough to take the pounding that the engine could deliver while pulling a full size trailer...up a very steep hill....for a long way...in the heat...with a head wind (made my point?).
The 0-60 times were about 6-7 sec. and a standing 1/4 mile could be covered in under 14 sec. To get more exact than that would be a waste of anyones time because Ford had long ago lost all interest in the Thunderbird being the money maker for the company. In 69 they sold 12 Mustangs to every t-bird, the birdies were being relegated to the dull duty of the family car for the upscale that didn't want or couldn't quite afford a Lincoln.
Glamor birds (fifth gen, a.k.a your bird) were soft and smooth and comfortable to drive. No longer twitchie and high-strung (if they ever were), that was now the Mustangs domain. Power everything and an interior that added weight for sound proofing with a remote mirror on one side only.
Although the F-86 fighter inspired grill gave everyone a reason to look twice, the Glamor-gals never made it into the rear air of muscle cars strata. But it can be done ( and is).
My 67 2 door hard top has a 390 with aluminum heads and intake, MPFI from and "MASS-FLO". Makes about 425hp and idles smooth. Has a 700R4 4-spd auto (I know, I know, G.M.) 3.25 9in. locker rear end from a 81 granada (because they had rear disc's and the rear axle bolts right up), she shoots and scoots.
From what I gather the 4 doors are rare so you may not want to drift too far away from stock (although you may want to drift away from that interior color choice). If the looks strike you right and the price is in line, you may want this 2 owner cream-puff. I don't really have a good idea of what it may be worth but I can advise that you price several from "AUTOTRADERCLASSIC" online and get a sample of whats out there and what it's going for.
I'm suprised that no one else more familar with your question hasn't answered yet but I hope this has helped.
Good Luck,
Lad