I was served via the regular mail with a summons to appear in court. I was not given these papers via a processor or even certified mail, just regular mail. I did some research on the plaintiff and found that it is a law firm in Colorado that has a LONG track record of scamming people on debit collections. Should I respond to this or just assume that it is a fake?

Check with your local court to see if they have filed suit

Yes, if it is a real summons and you don't appear, they win automatically,