KX450F right side lug (SFF TAC)

I don't know but you might be able to ask Ohlins, Factory Connection, Race Tech if the lugs are compatable.

I fear that the stripping process, which is done prior to a new coating, moves through the aluminum and damages the anti-friction coating on the inside of the tube.

I base this on the fact that just about all of the re-anodized tubes that I have seen and serviced have the anti-friction coating peeling off. I seldom if ever see that on other unmodified forks.

By the way, tubes and lugs are aluminum. You can choose between a Type 1 or Type II coating. Type is harder. Most "bling" anodizing is Type one.

On the lugs you could do either or get them power coated, but nothing is really going to hold up to the abuse that they will get.

The factor coating on the upper tube is Type II.

And if you want a bright finish the part needs to be polished before the anodizing is applied.

As for lugs, they nearly all use the same threading, such a M48x1.0. However, what matters more is the end of stroke bottom out. Most lugs have a tapered cone in them that matches up with the piston at the bottom of the cartridge.

FYI, the '18 450 TAC forks are 49mm the 250f SFF are 48mm so are not compatible. The only lug that may swap out is the '19 KX450 lug since they are 49mm Showa as well. Ohlins should supply their own bottoming cones to go into the Showa lugs and match their cartridge oil locks.

Might be your best bet to contact Showa directly and order an axle holder from 2019 KX450 as Slipdog mentioned.

Another option worth looking into is checking the 2018 RMZ 450 right lug axle diameter and offset.
If it's the same as KX's it should be a straight swap as well:
Showa 49mm fork lugs

On the other hand, paying over 150 EUR for a cast lug... I would learn to live with that balance chamber you have

19 lugs won't work they have a bigger axle. Would need both lugs, axle, and wheel. Not worth it.