Unless you test the oil, you really don't know.
Here's a Blackstone analysis on a Corvette Z06 after 12K mi between a change.
12,000 miles is a pretty long run compared to the average LS6, but this engine handled & with ease.
The data in the rightmost column shows results for the LS6 at an average oil run length of 3,800 miles. Your data at 12k ali came in at comparabie levels, implying much better than average wear rates. There's nothing to worry about in these results. The oil held up weil to the longer run, showing correct viscosity and no sign of fuel or coolant contamination, and both oil and air fitration lock fine. Bump the interval up to 14,000 miles next time and check back.
MI/HR on Oil
12,000
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