A Parker B grade gun is not that rare or valuable to warrant a lot of effort or expense, especially in 10 ga.

When you got done, you'd still have a restocked, funky barreled Parker that was too large and heavy to use for most interests. I'll bet it would have a market value of 60-75% of what you had paid to rehab it. You can buy a B grade Parker 10 for under $10K that still has it's own tubes and wood.