OK I just read your last post... If you can get the black frog for $75.00 BUY IT!!!!!!!!!!!!!!!!
I have a very nice RC hewer like yours (without a frog) and paid $350.00 for a frog from a VERY reputable dealer. The frogs are very hard to find and there are a lot od RC daggers without them. If you can get one for $75.00 you have a deal that is far better than the dagger itself!!!!!!!!!!!!!!
In my opinon!
PS: Where were you last year when I paid $350???
PSS: Yes, I think the whole thing IS worth "fixing up". Finding a lug may be near impossible, but if you could get the part machined (for near nothing) and painted and re-attached (super glue works great!) This knife, cleaned up, a new lug and the frog, you would havee an $600-700 knife. I would say "go for it!"
Good luck!