I don't think those numbers are actually indicating build dates, particularly the PC one. rth actual contract with Enfield was completed in 1959. I think the actual build date was probably earlier, as in '58. I know the export engines for the Chiefs were actually built before the Brits got the Connies which was in April '58. Some of the bikes were shipped in '59, but I doubt that any were shipped in '60. I think those PC***** serial numbers were probably put on by Indian, as they certainly don't follow the standard RE numbers. The shipping dates to the US were probably doled put ever several months even though production had been over for months. By 1960 the numbers and dates were assigned by sale dates, not build dates. As for the kidney shaped side cover, I think that was a distinctly Connie Chiefs that was on all of them that I've seen, as they had a different battery than the Brit ones. Did any of the Chiefs actually have the TT carb on them? All I've seen were Monoblocs. The Brit '58s had TT Carbs.
Bare