And we're trying to help ...

With specialty bits like 'Burb bodies ... there probably isn't a lot of people around with the up-to-date specialized pricing knowledge who can take your description and give you a dollar value. Hence the "research" thing

Start with Barry's article, only substitute "'54 Burb Body" for a whole truck, hit the resources mentioned and start searching the internet to get as close as you can and see where the prices lead you.
Heck I don't know ... Start with prices for complete burbs in similar condition and then start subtracting things/values until you get to a body. Then maybe add a premium back in for having done all the removal for someone ... adjust for condition of the shell ... I would imagine a '54/'551st body commands a little more than the average AD burb body ...?
Like Barry says, though ... the more reasearch you do, the better idea you get. And it all comes down to finding someone who wants it and meeting them on a price. Seat of the pants ...
Good luck!
And then, if you come back and are willing to share what you all ended up with as a price, it could help the next guy ... maybe ... Just a thought.
John