Engine fires were far more common during the time I was active as a technician, especially in the 70's. I did a lot of fire jobs. They were far from my favorite assignment.
A direct answer to your question is that there is not enough information here to even venture a guess. Everyone is different. From the pictures posted here I'm not sure if I would take it to part out if it was given to me. The damage looks extensive.
I disagree with not purchasing, not just because I was going to, but because you have to work out the sale prices of all the good parts and take what you have invested off the top. I have made a basic list and then there are more parts left in the car that you make the random $20-$40 on.....
+++ Rear TCE brake kit alone was $579 and all of that is there
+++Stage 2 Axles $400
+++Strut braces $200
+++stock wheels & tires $200
+++trans $1,000
+++exhaust $250
+++interior $2-350
+++rear bumper $250
+++skirts $200
+++DMD $30
+++SCT pro racer package $200
+++arizona dyno chip $100
+++UIM is probably good $150
+++GCs and Konis with camber plates $600
+++rear aussiebar 24mm $100
+++aftermarket door speakers $150
+++steeda billet pedals $40
+++door glass $40
+++trunk lid $50
Just on that stuff listed above would bring you around $4,600!
-the auction, shipping, etc.. for less than $2k. You have over $2500 worth of parts...... ???? Justify why not to buy it besides saying "it's toast". Buy to part it out not to fix. It has a salvage title that is why it is at a salvage vehicle auction facility.