L visa is routinely changed to RP in guanxi, and many, me inclusive, have done so previously there. in fact, a valid RP from another province may work against you in guanxi province and so i would follow turnoi's suggestion on.

there are so many farce employers around this country and this no L visa policy in guangdong and some other locations sucks as it plays into these employers cards.

OP, i wish i knew where in maoming you were as my mother in law comes from there and i've been visiting the area.

cheers and beers to our passport option as these farce employers will never give up exploiting us :)