I agree with Rhys, unless its stupidly cheap id buy one already registered (could end up being more hassle then its worth, time off work etc)
And plenty of imports came in under the 15 year old scheme
but they should still have 6U9000 then HCR32XXXXXXX or BNR32XXXXXXX
usually either on a plate attached to the firewall or engraved directly onto the firewall
ones that came in under SEVS either has a Pink or Green compliance plate