Now I just tried to google for the Thai word "รหัสชุมชน" (Chumchon code), and to my surprise I found quite a lot of hits. Among the first was a forum entry at the website of Ang Thong town municipality (เทศบาลเมืองอ่างทอง),
ชุมชนศาลเจ้าพ่อกวนอูเป็นชุมชนใหม่เกิดขึ้นตามประกาศเทศบาลเมืองอ่างทอง เรื่อง การกำหนดพื้นที่ชุมชน ณ วันที่ 19 พฤษภาคม 2552It says, that on May 19 2009 the new community "San Chao Pho Kwan U" was established, having 255 households and 513 citizen, and the geocode 15990014. Exactly the kind of code I was expecting, since Ang Thong municipality has the code 1599, and to get to the same hierarchical level as the villages two zeros are added between the chumchon number and the municipality code. The forum entry then continues with a short description of the boundary.
มีจำนวนครัวเรือน 255 ครัวเรือน
ประชากร 513 คน
Now continuing with this code, as well as with the code for Chumchon 13, I then found two Excel sheets, both from the SML program, the fund to support the Muban and chumchon originally started by the populist Thaksin government.
The first named Angthong.xls dates from August 2008, and contains only the codes 1 to 13 for Ang Thong town. The second, named chumchon.xls is from August 2009 and lists 4421 chumchon from all over the country. For Ang Thong it has 22 chumchon, including the one mentioned above. Thus it seems Ang Thong created 9 new chumchon in 2009, however only one is mentioned in the forum. Sadly, this chumchon.xls is definitely not a complete list, those few municipalities where I added chumchon to the XML files before are all not covered there. I have no idea how many chumchon it has altogether, none of the annual statistics I know of lists them. Only the news report I linked above for the SML program says there are 3414 in 2008.