Last night’s “Big Goodbye” discussion at Burbank’s Buena Vista Branch Library went nicely. A sizable crowd attended, and author Sam Wasson and Chinatown assistant director (and subsequent hotshot producer and author of “Magic Time: My Life in Hollywood“) Hawk Koch kept things frank and lively.

Chinatown is properly regarded as one of the most historically fastidious period films ever made, and yet there’s one small blunder at the end of the Mar Vista rest home scene. As Jake Gittes climbs onto the running board of Evelyn Mulray’s moving convertible as “the midget” pulls a gun and fires, you can spot a ’60s or ’70s-era white car driving along a boulevard in the dusky distance, 70 or 80 yards away.

And so, following my usual inclinations, I asked Koch if he knew of any insignificant errors aside from this one. He questioned the white car claim — i.e., “Are you sure? Then I didn’t do my job.” By all accounts Koch did a splendid job. Little errors like this happen all the time. (My initial posting of the white car photo happened a couple of years ago.)

Sam Wasson, Hawk Koch — Wednesday, 2.12, 7:45 pm.

Here, by the way, is a first-rate Chinatown location website, complete with Google Map links.