I completely agree with Rand and his extremely well worded assessment, in acquiring weapons one will make mistakes, and will gain knowledge in sometimes painful degree. While this knowledge is of course useful, it is better to learn as much as possible 'before' buying weapons and the degree of injury will be less. Hopefully the information shared on the forum here has helped others as I know it has helped me.
The next key is to find a dealer you trust and try to focus on dealing with them whenever possible. Obviously deals 'too good to be true' have increased in volume with the advent of computers and ebay et al. The sheepish ploy of many the coy seller who 'inherited this' , found it in an estate sale but doesn't know what it is etc etc.has all been tiresomely played out, and it is difficult to determine with unknowns when this might surprisingly be the case.
In those cases, research before bidding, contact dealers or professionals you trust.
Everybody makes mistakes, and the big boy auction houses are not immune. however with the knowledge base that seems certain with thier staff it would seem surprising that inaccuracy would occur. Naturally, money prevails and is known to turn heads away from such matters. In these busy times it has become to easy to blame volume, shortage of personnel and all manner of excuses for such things, and if the error is to advantage, well
As for the mounting of very old Indian tulwar blades in recent karabela mounts, the practice seems to have been around for a while, and I always wondered what became of the original hilts or if these were simply trade blades never used. In the instance I have seen the blade was indeed very old, probably latter 17th century.
All best regards,
Jim