barrel and receiver thread timing/indexing?

ok, so the beauty of the bbl lock nut design is pretty obvious. i just spun and headspaced a 'new' factory takeoff bbl onto a model 12 (happened to be a .204 replacing a .308, borrowing a bolt from another model 12 in .223), and the bbl roll markings ended up at 6:00 instead of 9:00... which leads me to ask:

assuming the threads on the bbl and receiver are not timed... is the bbl marked at the factory after assembly to the receiver?

curious minds are - well - curious if anyone knows and will enlighten me?

thanks!

Yes, they are marked after assembly.

After assembly and are proofed.

thanks for the confirmation. seemed it had to be so.