When a 'smith says 8-12 weeks you don't expect well over a year especially when he has all the parts --- and "loses" some expensive ones....... take your pic ---- is he to dumb to make an estimate, is he unethical enough to put other work in front of yours or does he just not give a crap.
What about "All of the Above"??
How, in the name of All that's Holy, can you "lose" a barrel?? There're kinda big!! Life's too darn short to play Russian Roulette with a custom gun project.
NB