Though I tested negative for GAD65 antibodies, I had a similar issue/concern regarding the c-peptide test at that time. It came in at 1.2 at a lab with a reference range (fasting) of 0.7-2.2. Endo declared it "obviously Type 2" since "c-peptide was normal," as was insulin level. Problem was that that test was not taken fasting, rather it was around 90-100 minutes after lunch. My BG at the time was 102 -- should have had higher c-peptide, I believe.
Five months later, my insurance insisted on a new c-peptide test before authorizing a CGM. That time it was done fasting at a lab with reference range of 1.1 to 4.4... M c-peptide was 0.7 (BG was 92). A year later the test was repeated at the same lab and it came in at 0.6 (BG 89). I had already been on insulin for 6 months at that point, so my doctor ordered no additional antibody tests were done; however, since there would be no change in my care plan (except maybe a better relationship with my insurance company...)
Regardless, I do make some insulin, which perhaps increases if my BG would go "very high" (I have never seen any test above 350), but to maintain anything like 'normal BG' levels, I have to take insulin -- even a 2-3-hour interruption in basal insulin can and has caused my BG to go up close to 100 points, especially in the early morning, due to our wonderful "friend" Dawn Phenomenon.
Regardless, congrats ofd sorts, @kaplageman on getting some clarity on your diagnosis -- and good luck!