Good point. Yes, I am aware that just a few companies make most oil filters but a part number should be sufficient because, if they change the seal, etc., it wouldn't work on any of the many vehicles that use that filter. That would be a critical error on the manufacturer's part and they would be sued so they would do everything to avoid that. Also, in 50 years of working on all cars, trucks, and motorcycles, I have never once seen an oil filter differ as you describe from another filter by the same manufacturer with the same part number. It sounds like you have, though. That said, I always compare new filters to the one I take off to make sure they are the same even when the manufacturer and number are the same. I've always changed my own oil on every vehicle I've owned since my first car in 1966 and I've never had a single leak or problem. To show how far I go back, I remember filters that went into a metal cannister with a bolt holding it on.
I've also owned cars with oil bath filters.
The mistake I've know people to make is not checking to make sure the seal came off with the old filter. That will definitely cause a leak if it isn't removed from the flange on the block.
