i work with alot of threads, not only that, i work for flowserve [an american pump manu'] so i see alot of thread drawings that make no sense, or a standard that the drafter made up on the particular day he had a fight with the missus... mind you, i do deal with drawings from the 30's up to current and even the drafters in our offices seem to have no idea or taken drafing lessons from Mr Squiggle.
SO, after that little rant... i dont think thats thread infomation. im guessing it would be batch codes. if the part numbers are the same i cant see why they would use different numbers for id'ing the same filters other than for batch referance.
reason why it would be batch numbers?
if you made filters at around 10,000 a day and a problem with the internals shows up 28 days down the line after some guys buy them and kill an engine or 100, the company can then hunt down specific batches, rather than the last 280,000 filters they made.
we stamp our spare parts like this for that exact reason, because even the "quality control" guys arnt perfect [regardless how great they think they are... **grumble grumble**].
iv never heard of an issue, but if the part number matches what a parts book says it should be fine.
if you cant find listings [like i couldnt in], use a toyota camry 3lt v6 filter, just the same, fit perfect and they are the smaller ones so easy to fit. with the smaller filter, id believe it wouldnt hurt to change it more often to make up for the size, and its now easier to change anyway.