I'm pretty sure the insurance company will know the category when you give them the reg.
I'm even more sure they will try to find any way not to pay out on a claim if they can help it, non disclosure is giving it to them on a plate.
/Edit - I guess I should come straight as to why this bothers me, I was hit by an uninsured driver, they picked my bike up from underneath their car then drove off leaving me in shock with a fractured elbow and a lot of cuts & brusies. Uninsured losses amounted to about £1k, I've managed to replace my lid, boots & gloves but my jacket is still on the list and I lost 3 years NCB (it's your fault for getting hit by a hit & run). If the diver had been properly insured he wouldn't have left me bleeding at the roadside....Even as a bike rider you can do a lot of damage, so I for one would appreciate it if you got the appropriate insurance for your bike.