I don't see why not? I have often used Tamiya white primer asa finish coat for the underside of US Navy aircraft... By the way - IMO it's better to apply a layer of grey primer and then use white over that. This way you get a vey good white surface in two layers. If you start with white on a model made from different materials the differences may show through and the second coat of white might not be enough to even them out.
Hope this helps - have a nice day
Paweł