Hi Caremount,
It's good to know that you are happy with your new PS2 system and that everything runs well.
To answer your question, I'm not entirely sure whether yours is an Orriga chip (it could be a better chip which does similar functions). The most important thing is that your system runs well and that's great. I have not tried running on an orriga chip myself, the system hang issue was brought to my attention from a friend of mine.
If for any reasons in the future you might want to change to a no-swap mod, be sure to read up on it on the internet before deciding on anything.
It's quite easy, just go to www.google.com and search for PS2 mod or equivalent and you will get to see an entire list of documents relating to modifying PS2s.
Hope this helps!
Regards,
Andrew