"I'm still amazed that the outdated or patent ended old Rolex or Tudor cases are not officially made by third parties. It sure would simplify things."
They are being made...Yuki, Phong, MBK, cartel etc. They are illegal only because they have trademarks. Remove the trademarks and they are 100% legal.
Otoh...if you send a 100% genuine 5513/1680 etc to RSC and it needs a mid case, they will sell you one for $2500+/-. What is the real world difference between this $2500 mid case and a Phong mid case for $900, both with genuine case backs? Nothing.
If you had the original serial number engraved on the Phong case, the watch would be worth quite a bit more 'out in the wilds' than the same watch with a genuine RSC '444' case...until you tell the truth about it. A '444' case will probably never be worth as much as an original case...or a Phong etc case after the second or third owner. It's a fact of life.
No telling how many aftmkt cased watches are out there being 'innocently' sold as genuine every day.
Back 25 years ago when a 5513 or 1680 went for $1500 or so, I used to see 'dealers' buying them at watch shows by the dozen. They would take them home and make 'premium' watches using the 'best of the best' cases/dials/movements/bracelets, have them professionally detailed, and sell them as 'mint' or 'near mint' for a LOT of $$ to 'serious' collectors. Then they would put what was left together in ascending order and sell the best examples on mail order lists sent out to regular collectors. The worst examples usually ended up for sale back at watch shows or parted out.
If you have a 'vintage' rolex and you did not buy it new...you might have a Frankenstein.
If Ya can't get married to yer sweetheart cause there is a law against it...you might be a redneck.