Welcome to Numista.
The difference between the 3rd and 4th portrait is so easily to be seen. The 3rd portrait (
https://en.numista.com/catalogue/pieces1643.html) is of a young king with his portrait far from the outer circle everywhere. The 4th portrait (
https://en.numista.com/catalogue/pieces22038.html) is of an older king and his portrait nearly touches the outer circle, especially below the bust. So your coin is without any doubt a 3rd portrait.
Now we only have to check the correct date (the highlighted section on your picture). As a fresh member you can't know the whole site yet, but in the tab "Numisdoc" we have a section "Dates and calendars" and there you'll find a Thai calendar as well:
https://en.numista.com/numisdoc/calendar-thai-33.html
But you could have found it also when you look closely after the year lines (
https://en.numista.com/catalogue/pieces1643.html). After every year line the date is written in Thai so looking at your coin and looking at the year lines you would have discovered yours is 2548 (2005).
