Yeah, it is good in the Fridge. Towards the end, do “smell test” it.
If I recall, packaged lunchmeat is stamped with a date but it also says somewhere on the package to use within 7 days of opening. I would not eat lunch meat that has been opened now in Sept!
Now, now. Those are specifically marked as “uncured.” (Which, as you hint at, is just complete bullshit. Celery powder/juice contain plenty of curing salts in naturally occurring nitrites/nitrates.) As a general point, you don’t need nitrites/nitrates to cure, salt will do. But with salt, you usually have to use a lot more of it to protect against microbial action (for example, prosciutto and jamon iberico is only salt-cured.) Plus nitrates/nitrate (whether sodium nitrate/nitrite or celery products) help give cured meat a pink color. (Salt-cured meats will usually turn brownish.)
Some of the sausages like salami and bologna are cultured with bacteria. Live culture helps extend the shelf life of the product by creating an environment less hospitable to other bacteria. If not dried those meats need salt and nitrates for a long shelf life.
Yes, they will have starter cultures, too, given them their classic “tang” (at least in the case of salumi), but they are also salted and often have some type of nitrite/nitrate cure in them, as well.