Some of the Toyota counterbalances I look after came with the 2nd horn button factory fitted.

Cleaning & greasing the horn ring's beind the steering wheel is part of the official Toyota service at certain intervals.

To be sure, our Toyota and Komatsu trucks with the 2 separate horn buttons, were built at the respective factories by the OEMs.
These trucks were spec'd out to have dual horn buttons when the trucks were ordered/bought.

there is considerable liability incurred whenever you change anything from the original [safety and instructions to use, in the operator's manual] OEM placement, and when the operator hits a pedestrian while trying to blow the horn, from the OEM placement, where they were documented to have been trained how to blow the horn, will give the forklift operator a 'legal and legitimate' excuse, but will create a trail of paper that will lead right back to whomever wrote a work-order that said "install horn button" in some place other than the OEM location, with parts other than those as certifiable as 'at least as safe as the OEM'.
Please always be sure the repair you make meets "industry standards" and is at least as safe as the OEM repair that uses parts at least as safe as OEM parts.

Yes, the horn is a safety device. Not just applicable to Toyota brand either.
All safety devices need to be maintained in the OEM configuration to assure the operators can habituate themselves to the exact location of the controls for the safety device.
Moving a horn button to a location different than the OEM placement removes the reflex action taken (by the operator to sound the horn) from being the correct action when a situation suddenly pops up where the horn should be sounded.
This becomes even more critical in a large fleet of forklifts where an operator might work for weeks without driving the same forklift twice.
Moving the location of a horn control button?? Might be "legal", but it is not smart.
Now, to be honest about my somewhat unique position, I will admit that all our forklifts do in fact have a second horn control button/switch mounted on the dashboard near the key switch. That second button is there as a supplemental horn button or auxiliary horn button to assure the truck horn can still be used until our shop addresses the report of an OEM steering wheel horn button inoperative. Our policy is that BOTH horn buttons must be in working order at all times, or place the truck out of service.
Horns not working is as bad as brakes not working with regard to how we address the issue at our shop.
We want a truck with an inoperative horn placed out of service and presented to our shop ASAP when it is discovered.
Some operators are good about complying, others would rather pass the buck to the guy on the next shift.
We have assigned operators that do a daily inspection of all the forklifts to augment the required pre-trip inspection the individual operators are "supposed to do".
Our assigned inspector/operators do in fact report more defects than the regular operators, and that is why we have a redundant plan in place.
OK, rant over.

@L1ftmech - nice to see someone following Toyota's service instructions.

I to have never had a horn contact ring fail either.

To be cheap, I always just clean up the areas of high resistance that develop on the two metal discs which are held onto the steering wheel with 3 screws each.
Remove the two discs and buff every place where contact is made and problem solved. Still have the horn button in the center of the steering wheel on every forklift. No hunting for it when you need it.

we run a lot of 8fgcu25's and the horn button typically goes out on those too. I'm gonna say that its from the drivers pushing or hitting the horn on the wheel and wheres out/ruins the contact. To be cheap, we just put a regular push button on the side of the steering column using the horn wiring in the column. Horn works with the push of the button......problem solved

If you take the steering wheel off you will see there is contact brushes that can wear out and fail.