This type doesn't appear to be widely collected or popular as I find nary an elaboration on this coin, apart from numista. I've come across a few that appear too high grade to attribute 0.4 grams of underweighted-ness to wear, and others that are as much as 0.6 grams overweight. Everything else seem to check out though. I'm not a native Thai speaker too so if there are resources available, I can't find them easily. Did they really have such loose standards at the royal thai mint at the time?