As I was just saying in the previous post, I can only tell you that during MY ownership of the vehicle (last 2 months), the AC system was NOT opened. The previous owner told me that he has done no work on the AC system either. The hoses don't look like they have been recently replaced, but the whole set-up looks quite clean from the visual inspection - no oil residues that I found so far.

I did ask a question specific to my car. Which is the low-side service port? Is it the one by the radiator up front behind the grille? That's what I've been told, but I want to confirm that.

So can I or can I not measure the pressure at the low-side service port with a tester gauge to find out whether refrigerant needs to be added?