Inconsistent Camshaft lobe wear

Hello there to all! I just purchased a beautiful 1982 300D TurboDiesel. Previous owner states that the car has the low 90K miles showing in the odometer, and based on the gorgeous interior, exterior and engine bay, I'm guessing that it's probably true. I pulled off the valve cover to inspect the valve train and noticed that cylinder 1 and 2 lobes on the camshaft are scored. All the other lobes from cylinder 3-5 are beautiful. Most of the input here seems to indicate that excessive camshaft lobe wear is attributed to both lack of frequent oil changes and, improper valve adjustment over time. Given this inconsistent pattern of wear, I'm wondering if my problem is more likely to be an improper valve adjustment of cylinders 1 and 2 rather than the lack of frequent oil changes. Additionally, everything under the valve cover looks remarkably clean and free of sludge and any build up. My question then, is if only 4 of 10 camshaft lobes are scored (both intake and exhaust of cylinders 1 & 2), while the others appear in good shape. And, because the head and all components appear very clean, would anyone agree that this seems more like an issue of excessively loose valve adjustment over time and not necessarily a lack of proper oil changes specifically due to the inconsistent wear pattern? Anyone have any thoughts? Thank you for your consideration and imput. JB