Hard to say what it's worth. It's like asking how much an LS6 Chevelle is worth. Depends on what parts are there, missing, etc.
The 69 Trans Am only had two engines available: the RAIII was standard, the RAIV was optional. No exterior color choices (there were all white w/blue stripes), while the interior colors varied. Most interiors were black or blue. That being said, ALL 69 Trans Am's had a Ram Air system. If the car you're looking at is missing the Ram Air system, or any part of the system is fiberglass (upper/lower pan), then they're reproduction pieces. Most of these parts are now reproduced in steel, but the 69 Firebird/Trans Am Ram Air system was very complex, and had over a dozen special pieces. It's expensive to replace it all. This Ram Air system was a one year only application. The 67/68 Firebirds used a much simpler system, and the 70-up Firebirds had a totally different configuration. Note: the 1969 RAIII baseplate pan is reproduced in steel, but not the 1969 RAIV.
RAIV cars were NOT available with a/c, and the standard gear ratio was 3.90 posi (used a 4-pinion HD rear end). The 69 Trans Am hood was steel, and if it's missing, or is made of fiberglass, they are VERY expensive to replace. A few have sold on E-bay recently for over $10K.
The rear wing should be a 3-piece construction. Look under the wing at the pedestal mounts. If there's a division line there, it's a real 69 Trans Am wing. If it's one piece molded, it's a repro. The cowl tag should have a D80 designation for the Trans Am rear wing. The body color must be 50/50 (white/white). Any other combo and it's a fake. Lots of other small items to look for, but a check with PHS will let you know if it's a real Trans Am or not.
Typically, a 69 Trans Am will bring 25K-35K restored, and a RAIV car will bring 30K and up. If it's a real RAIV car, they're pretty rare.
RAIV - Turbo 400 : 9
RAIV - Manual trans: 46