I'm with Murano on this. Modern electrics, modern engine management & variable fuel injection mean that plugs will last 40 - 50,000 miles with no significant wear.
My MR2 (1991 convertible), owned for 2 years before me by a friend, used by me for 3 years, before selling it back to said friends son, is still on the same set of plugs as when he originally bought it & each time it has had a service, the various garages used have reported the plugs back as 'like new' without any adjustment required...
Compared with my MK3 cortina that had new plugs & points at every 2000 mile service, because they looked knackered... sounds like a way to get the service costs up... I'd certainly ask to see the old ones as I can't believe any mechanic worth his salt would throw away perfectly servicable bits...