Not that I know of without a reg number. Is there a tax disc or paperwork with a number on it? If not, and I guess that it has been used off road, then it is a gamble. Depending on the year, condition and what is missing off the bike you have to weigh up the risks. If you plan to put it back on the road then you have to gamble it is not nicked or written off. If there are bits missing, and depending on the age, then you have to look at the cost of these so maybe a couple of road tyres, chain & sprockets, bearings, lights, dials, V62, MOT, mirrors, ignition switch etc you may be looking at a £300+ spend.