Oregon LGX is what you want, lots of places have lpx. As for Stihl It would be 23RS the new version is the 3690 code a sort of NK type of product which the local place has to make loops out of. They did not know the difference and put it together with the preset parts for the previous model that was 0.063" at the top of the drive link. A number of years ago I had a loop made elsewhere and it did not have safety features like bumper tie straps. I never tried to get a Stihl dealer to sell me a roll don't see why they would not.
https://www.sawsuppliers.com/collections/saw-chain/pitch_-325https://americanforestry.com/produc...owercut-325-saw-chain-050-gauge-100-foot-reel
Just a couple probably on the low price end of places.
Baileys has a product as well I get it in the skip sequence which I don't know of any other source for skip .325
I kind of like the fancy drive link features for oil movement which is Stihl at the moment in .325 chisel.