I have ridden horses who had a permanent limp from a injury healed.
Vetted and vetted again top to bottom and no pain was involved nor a issue anymore but a limp existed still.
One horse had one leg shorter than the other...
You could not leave a hoof that long safely to "even" out the difference in height...yes it was that noticeable but there was no pain but a short leg so...a limp.
I have also ridden a horse who had their ankle medically fused after a injury.
Once healed no pain and the horse loved to go, but because of the fusion a limp.
Neither horse was in pain, but both were watched carefully and fully vetted and reason known as to why they limped.
To just ride a horse that limped without that knowledge of pain, healed or healing injury, ongoing muscle, tendon or bone changes happening....
Put bluntly, I value my hide more than to sit astride a horse with a noticeable hitch in the gait and not know if a catastrophic failure of the body was taking place...that could risk my life and safety besides that of the horse.
No, without true knowledge of what is happening, disclosed to me that safe to ride...my feet would also be firmly planted on the ground.
I would not accept a "guesstimate" by the owner. Either they know or they don't.