According to the Vintage Celebration section of the Santa Fe Century Website:

What qualifies as a Vintage Road Bicycle?
Out of respect for the now famous L'Eroica events world-wide, we'll follow Giancarlo Brocci's original criteria for Bici Eroiche: Your bicycle should have been built before 1988 (although vintage style bikes with steel frame from recent construction, with vintage look and characteristics, may be used). If the bicycle is geared, it should have shift levers on the down tube of the frame (exceptions include pre-1980 non indexed bar-end shifters and rod/hand manual operated front derailleurs). Your pedals should be with toe clips and straps, or for older bikes, you should have the original pedals, or something like the originals. The brake cables should pass outside and over the handlebars (cables can pass inside the frame). Tubular tires are admired, but optional.

My bike certainly qualifies according to those rules, except my Sturmey Archer shift lever is on the handlebar rather than the downtube, but that's to be expected - nothing about LED lights or alloy rims being disallowed. Nothing about repaints either.