Definitely need a mask, not sure what rating as I have an air fed mask, but epoxy primer doesn't usually contain isocyanates but check the safety data sheet to make sure
You can get good quality masks for around £20 that are ok for short, limited use with 2k paints, so they should be fine with non iso epoxy primer like Lechler 2107. I have this one, bought from a different supplier though, and it is good for aerosols, spraying Gravitex etc., so I would think it would be fine with epoxy primer. Big step up from the little elasticated masks, but as always, follow the instructions and store properly.
Not sure about the description of that mask as the ad claims it's a full mask when the picture shows a half mask, even then its not one that gerson claim as 'Usable with isocyanate's in accordance with label warnings and limitations.' as per there catalogue https://www.gersonco.com/wp-content/uploads/2019/07/English_Product_catalog.pdf
I would always check manufacturer’s information rather than rely on a resellers ad