I'm working on an upper and just wanted to make sure I'm not making a mistake. I've looked around and can't find where any info on the exact product I've used in the past. I have used this grease in 3 builds so far probably from 1 to 2 years ago. Here is a link to the product. If it's not good to use on barrel nuts what should I do to fix my previous builds?

https://www.oreillyauto.com/detail/c/masterpro-chemicals/oil--chemicals---fluids/grease---lube/grease-cartridge/80e03b4d1ff6/masterpro-14-ounce-multi-purpose-lithium-grease/mp02/90358?pos=3



Thanks for any help in advance.

I don't believe so. You can always lookup the SDS

No, that's just a lithium multipurpose EP grease.  If it contained graphite (or moly), it would exist as a fine solid powder that would make the grease appear grey or black, and it's an amber grease.