identifying early Spit cranks?

["Gambony, Jim" <jim.gambony@eds.com>]

Howdy all!

Is there an easy method (part # maybe) to distiguish between the different
cranks used in the pre-1500s?  I ran across a gent with a crank that's
definitely Triumph 4 cylinder pre-1500 that's been cut .020 rods/.020 mains
and is available for roughly $150+shipping.  I don't know a quick way on how
to id to tell if it's 1147 or early 1296 or later 1296 without a micrometer.
Definitely won't fit my 1500 though.

TIA

Jim