The Chanthaburi license plate [Gazette] shows gemstones to the right and some kinds of fruits (Rambutan, Mongosteen and Durian) to the left. In the background is the rising sun pointing to the location in the East, and a hill with two waterfalls. Fruits (and especially Durian) as well as gemstones are the most important products from this province, and in the hills of the province many waterfalls are popular touristic locations.
In fact, the graphic is identical with the one published in 2004 [Gazette], or instead of a scan the announcement now contains a vector drawing (however saved as a JPG in the PDF), so only the colors look much more clear now. I have uploaded the old graphic to the Picasa album as well.
For Lopburi [Gazette] I am not sure what the graphics is supposed to mean. The statues in background look like Khmer style stone carvings and thus probably point to the many Khmer ruins still present in the province - most notably Prang Sam Yot as one of the attractions of Lopburi town. I however cannot get the meaning of the four puppets in front - or are they in fact monkeys, as the wild monkeys in the city are also very iconic for Lopburi.
The graphic looks very similar with the previously announced one from 2005 [Gazette], only the arrangement of the puppets and statues is changed a bit - see it here.