I seem to be fortunate with my purchases. This pair was bought mainly because I like the Temburong D3 cancellation. But imagine my surprise that the two 3c stamps were significantly different from each other. The 1908-1922 set was issued over a few different years using 2 slightly different plates for printing.
The stamp on the left has the Brunei D4 cancellation but looks like the last 2 digits of the year is missing. This 1908 3c stamp is also Type 1. The second stamp has a very nice large part Temburong D3 cancellation and also is the more uncommon Type 2 stamp issued in 1916. Temburong used a district postmark like Labuk & Sugut and Bangar is the main town.
In Type 1, the lowest line of shading on water is dotted using 2 different plates in the printing process, one for the vignette and a separate one for the frame. This was in the initial printing of the 3c which was issued in 1908.
With Type 2, a single plate was used. It was possible because this is a monocolour stamp. The dots at the lowest line shading are no longer present in this plate. This was a subsequent printing and the stamp was issued in 1916. This is the more valuable type and worth 30x more used. With a Temburong cancel, it is very fortunate.