How Fuzzy was the 1978 model 18038 / 18078 Years?

Would love some comments on an odd situation.

I bought what I thought – and was told by local jeweler – to be a beautiful 1978 18078; beautiful tight bark bracelet and bezel. Upon deciding all-gold was not for me, I sold the watch at a fair price, less than what I paid. Box, manual but no warranty or other papers. The buyer got back to me saying his Rolex dealer says it is all genuine but case is marked a 18038, not a 18078. In fact, he says the dealer thinks the last "8" was added and the watch comes up in the registry as an 1803. Wha?

I know the 18078 and 18038 are identical except for the bark. Did Rolex do any special orders or just switch out bracelets and bezels in the late 70s? I have seen numerous 18038s with bark bracelets and bezels for sale. So I didn’t think so unusual. But what about the claim of engraving an extra 8 to make the case a 18038? Different calibers, different crystal… would this even be a possibility?

Ok, 46 years is a long time and I can imagine the industry was a more "adaptable" in transition years. Would love to hear thoughts on 18038s with bark and the claim of engraving a case to coincide with a 18038 model. Thanks!