All About Pocket Knives

Hi Guys , been offered a Wilkinson jungle knife, indian para and a Cogswell & Harrison knife , does anyone know if this is good or were they copied? Or does someone know a site i could find out some info about them before buying? been offered $500, and $1000, $1000 respective , knives in very condition
Any help appreciated
cheers
Phil

Would like to see some closeups of the Cogswell & Harrison.I have one that has such a stamp. They are London gunsmiths that specialize in high dollar long guns. Don't know anything about the others you mentioned.