Looking at Hiroshi's site, I'm not sure the dropout dating is so clear. And in any case, the frame in question appears to have dropouts from 3 different eras. And the possibility that some were changed out. And it is also possible as others have pointed out that early dropouts can be dug out of the bin and used on a later frame.
Just seems unlikely to be an early frame given the late lugs and the late apparent headbadge drilling.
Mike Kone in Boulder CO
> I only wrote the following in response to Mike Kone:
\r?\n>
\r?\n> Mebbe so, but what about those open C dropouts. Wouldn't these pre date the
\r?\n> dropouts with the spring holes?
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\r?\n> Jay Sexton
\r?\n> Sebastopol, CA
\r?\n>
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\r?\n> To my eyes, the frame looks nearly identical to the one I had on ebay last week
\r?\n> that didn't hit $700 (sold later off ebay for a good bit more, all very
\r?\n> surprising). The dropouts on Dale's bike do look like later ones (the clue to
\r?\n> the one I was selling as likely having had a dropout replacement I think). The
\r?\n> one I sold was certainly built around 1959 to 1961. I'd peg the date of the bike
\r?\n> in question as being from 1958 to even as late as 1967 - with the dropouts
\r?\n> pushing the build date to the later period as wise Harvey Sachs points out.
\r?\n>
\r?\n> Cinelli Serial numbers from what I can tell are generally meaningless - a
\r?\n> "stroll" through the Cupertino log book years ago showed very weak correlation
\r?\n> between year and serial number, although bikes sold in very close time to one
\r?\n> another often had close numbers. But those batches of similar numbers were not
\r?\n> sequential. Quite maddening!
\r?\n>
\r?\n> Another clue would be if the bike in question accomodated the reproduction
\r?\n> headbadge without difficulty - if so it is a late 50's bike or later. The
\r?\n> really hard-to-find earlier bikes used a larger size headbadge with screws for
\r?\n> fastening farther apart.
\r?\n>
\r?\n> Mike Kone in Boulder CO